Biomechanics doi: 10.3390/biomechanics4010011
Authors: Jullyanne Silva Tiago Atalaia João Abrantes Pedro Aleixo
According to the World Health Organization, one-third of elderly people aged 65 or over fall annually, and this number increases after 70. Several gait biomechanical parameters were associated with a history of falls. This study aimed to conduct a systematic review to identify and describe the gait biomechanical parameters related to falls in the elderly. MEDLINE Complete, Cochrane, Web of Science, and CINAHL Complete were searched for articles on 22 November 2023, using the following search sentence: (gait) AND (fall*) AND ((elder*) OR (old*) OR (senior*)) AND ((kinematic*) OR (kinetic*) OR (biomechanic*) OR (electromyogram*) OR (emg) OR (motion analysis*) OR (plantar pressure)). This search identified 13,988 studies. From these, 96 were selected. Gait speed, stride/step length, and double support phase are gait biomechanical parameters that differentiate fallers from non-fallers. Fallers also tended to exhibit higher variability in gait biomechanical parameters, namely the minimum foot/toe clearance variability. Although the studies were scarce, differences between fallers and non-fallers were found regarding lower limb muscular activity and joint biomechanics. Due to the scarce literature and contradictory results among studies, it is complex to draw clear conclusions for parameters related to postural stability. Minimum foot/toe clearance, step width, and knee kinematics did not differentiate fallers from non-fallers.
]]>Biomechanics doi: 10.3390/biomechanics4010010
Authors: Lara A. Thompson Roni A. Romero Melendez Ji Chen
As the aging populations, both nationwide and worldwide, rapidly increase, falls leading to unintentional injury and death subsequently increase. Thus, developing an understanding of biomechanical postural control strategies used to maintain balance in aging healthy adults, and those that have suffered stroke, are critical. Here, we were interested in how one’s body segments stabilize relative to one another, and in space, in order to maintain balance. To accomplish this goal, we studied 30 healthy individuals and 8 survivors of stroke between 60 and 85 years old, both before and after several weeks of sensory training. Motion capture data were acquired to assess participants’ body kinematics during walking: forward (easiest), forward-tandem, backward, and backward-tandem walking (most challenging). Deviations (via the observation of the absolute angle with deviations, or AADs) of the head, thorax, and lumbar areas relative to an earth vertical reference, as well as how one body segment stabilized in space or relative to the inferior body segment (via the observation of anchoring indices, or AIs), were explored. The results provide metrics (AADs and AIs) that can assess aging posture. Further, the results show an initial indication that, for aging individuals, training could lead to improved head and body stabilization in space.
]]>Biomechanics doi: 10.3390/biomechanics4010009
Authors: Jordi Arboix-Alió Guillem Trabal Bernat Buscà Dani Moreno-Galcerán Bernat de Pablo Hugo Sarmento Vasco Vaz
This study aimed to investigate the influence of stick grasping on the performance of elite youth rink hockey players in 10 m linear sprints and 180° change of direction (COD) tasks. Forty-nine rink hockey players (age = 18.40 ± 2.12 year; body mass = 73.52 ± 6.02 kg; height = 1.82 ± 0.07 m; BMI = 23.61 ± 1.69; sports experience = 6.42 ± 1.41 years; 4.89 ± 0.68 years’ post-peak height velocity) participated in this cross-sectional study. Measurements included 10 m sprint time and COD 180° performance with and without stick grasping. Results revealed non-significant differences when carrying a stick in the 10 m linear sprint (1.90 s ± 0.08 with stick vs. 1.89 s ± 0.08 without stick; p = 0.71; d = 0.05), neither did COD 180° for the left limb (2.75s ± 0.11 with stick vs. 2.76 s ± 0.11 without stick; p = 0.91; d = 0.02). However, for the right limb, significantly better performance in COD 180° was found when players held the stick (2.72 s ± 0.11 with stick vs. 2.75 s ± 0.09 without stick; p = 0.03; d = 0.32). These findings imply that the distinctive biomechanics and requirements of rink hockey, especially the lateral movements inherent in skating, might alleviate the negative impacts associated with implement grasping observed in other sports. This study highlights that stick grasping did not hinder COD ability and may even have a facilitating effect on certain movements, emphasizing the importance of considering sport-specific biomechanics in rink hockey performance analysis.
]]>Biomechanics doi: 10.3390/biomechanics4010008
Authors: Francine Pilon François Prince
The Olympic/Paralympic Games are world events that promote countries and their participants, and more particularly, those winning medals. The potential link between a country’s scientific productivity and its podium wins remains unknown for the Paralympic Games. This study aimed to (1) quantify the link between the production of Paralympic scientific articles and the medals won by countries during Summer/Winter Paralympic Games between 2012 and 2022, and (2) select the five most important articles published for all Paralympic sports. A bibliographic search of the Web of Science, PubMed, and Google Scholar databases was conducted. From the 1351 articles identified, 525 fulfilled the inclusion/exclusion criteria. The results showed a greater (7x) production of scientific articles relating to the Summer Paralympics compared to those relating to the Winter Paralympics. For the Summer Paralympics, there was a strong correlation (r = 0.79) between the number of medals and the number of scientific articles produced by a given country, while a low correlation (r = 0.12) was observed for the Winter Paralympics. Biomechanics-related articles represent almost 50% of the overall Paralympic publications. In conclusion, there is a strong link between scientific productivity and the number of medals won for the 2012–2022 Paralympic Games. Parasport Federations are strongly encouraged to promote the publication of more Paralympic research articles.
]]>Biomechanics doi: 10.3390/biomechanics4010007
Authors: Andrew Craig-Jones Daniel R. Greene Jonathan J. Ruiz-Ramie James W. Navalta John A. Mercer
To the purpose of this study was to compare muscle oscillation, muscle activation time, and oxygen consumption while wearing compression pants vs. a control garment during running. Methods. Eleven injury-free and recreationally active participants (26.73 ± 12.74 years) were recruited for this study. Participants ran in full-leg compression pants (COMP) and a loose-fitting control garment (CON). Participants ran for 6 min at three submaximal speeds: preferred speed (PS), preferred speed minus 10% (PS − 10%), and preferred speed plus 10% (PS + 10%). The muscle activity of the leg was measured through electromyography (EMG). Muscle oscillation (MO) was measured with accelerometers attached to the thigh and shank. The rate of oxygen consumption (V.O2) and heart rate (HR) were recorded during each condition. MO was assessed over the 0–60 Hz range by averaging power across 10 Hz bins per leg segment. EMG data was processed to identify the activation time. Following each condition, a belief score was recorded. Dependent variables were each compared between conditions using 2 (garment) × 3 (speed) repeated measure ANOVAs (α = 0.05). The relationship between the belief score and dependent variables (compression-control) was analyzed using Pearson’s product-moment correlation (α = 0.05). Results. MO was lower with the full-leg compression pants vs. the control garment (p < 0.05). The muscle activation time for each muscle was shorter while wearing the full-leg compression pants (p < 0.05). Neither the V.O2, RPE, SF, nor the HR were influenced by the garments (p > 0.05). There was no significant correlation between changes in the dependent variables and belief. Conclusion. Wearing compression pants resulted in reduced MO and activation time; however, these changes did not translate into a reduction in V.O2.
]]>Biomechanics doi: 10.3390/biomechanics4010006
Authors: Analina Emmanouil Elissavet Rousanoglou Konstantinos Boudolos
This study aimed to determine the minimum number of repetitions for a high reliability of movement timing in fundamental physical fitness exercises using inertial sensors. Fifteen young men and fifteen women performed eight exercises (two-leg hop, forward lunge, squat, sit-up, shoulder abduction, hip abduction, back extension, and push-up) (preferred tempo, 3 trials, 20 repetitions per trial). The movement timing (cycle of movement in seconds and its phases in seconds and %tcycle) was tested for intra- and inter-trial reliability (SPSS 28.0, p ≤ 0.05). Just two repetitions were adequate for excellent intra- and inter-trial relative reliability (ICCs ≥ 0.75, isolated exceptions only for durations expressed as %tcycle, in only three out of the eight exercises: hip abduction, back extension, and push-up), as well as for high absolute intra- and inter-trial reliability (average SEM% at 5.9%, respectively, and 6.8% and average MDC95% at 13.7% and 15.9%, respectively, which was consistently higher than the upper boundary limit of SEM%, and a rather low CV% ranging from 1.5% to 4.9% and averaging at 3.1%). A total of four repetitions, excluding the initial and the final one, appears adequate for high overall reliability of movement timing in the eight physical fitness exercises examined.
]]>Biomechanics doi: 10.3390/biomechanics4010005
Authors: Elissavet Rousanoglou Apostolina Foskolou Analina Emmanouil Konstantinos Boudolos
Head standing (HS) in concurrence with diaphragmatic breathing is an atypical deviation from daily activity, yet commonly practiced. The study aimed at the inertially sensed effect of diaphragmatic versus normal breathing on the abdomen wall kinematics during HS. Twenty-eight men and women maintained HS and erect standing (ES) under normal and diaphragmatic breathing. An inertial sensor (LORD MicroStrain®, 3DM-GX3®-45, 2 cm above the umbilicus, 100 Hz, MicroStrain, Williston, VT, USA) recorded the 3D abdomen wall angular displacement (AD) (bandpass filter (0.1–0.5 Hz)). ANOVAs (p ≤ 0.05, SPSS 28.0) were applied to the extracted variables (AD path: magnitude, individual variability-%CVind, and diaphragmatic to normal ratio). Reliability measures (ICC and %SEM) and the minimal detectable change (%MDC90) were estimated. Diaphragmatic breathing increased the AD path (p ≤ 0.05) with the diaphragmatic to normal ratio being lower in HS (p ≤ 0.05). The similar AD time series (cross-correlations at p ≤ 0.05) and the ICCs (>0.80) indicated excellent reliability with the similar across conditions %CVind (p ≤ 0.05), further enhancing reliability. The %MDC90 was consistently higher than the %SEM upper boundary, indicating the differences as “real” ones. The results contribute to the limited data concerning a widely practiced atypical deviation from daily activity, as HS in concurrence with diaphragmatic breathing.
]]>Biomechanics doi: 10.3390/biomechanics4010004
Authors: Morteza Farivar Sara Harris Anton Agana Adam C. King
The purpose of this study was to examine the cross-over influence of lower limb fatigue on postural control. Using two experiments, cross-over fatigue was investigated using a proximal (Experiment 1—single-leg squat) and distal (Experiment 2—calf raise) muscle group. In Experiment 1, 15 healthy young participants underwent a single-leg standing task on both the right and left leg, with variations of having eyes open or closed and on stable or unstable surfaces, performing each task for 30 s. For Experiment 2, 20 individuals performed single-leg balance testing for the right and left leg and stable and unstable surfaces. Center-of-pressure data were collected during the balance tasks and were analyzed with linear (standard deviation) and nonlinear (detrended fluctuation analysis) metrics. The results lacked significant differences (p > 0.05) for cross-over fatigue effects on the non-exercised limb, which exhibited similar levels of postural sway between the pre- and post-fatigue balance tests. These tasks may have lacked an appropriate level of duration or intensity to cause a significant effect of central fatigue on the nervous system. The findings underscore the need to better understand how a specific fatiguing task during unilateral rehabilitation may alter postural control.
]]>Biomechanics doi: 10.3390/biomechanics4010003
Authors: Grayson M. Talaski Anthony Baumann Bshara Sleem Kempland C. Walley Albert T. Anastasio Ken Gall Samuel B. Adams
The use of midfoot wedges for the correction of flatfeet disorders, such as progressive collapsing foot disorder, has increased greatly in recent years. However, the wedge material/composition has yet to be standardized. Metallic wedges offer advantages such as comparable elasticity to bone, reduced infection risk, and minimized osseous resorption, but a comprehensive review is lacking in the literature. Therefore, the objective of this systematic review was to organize all studies pertaining to the use of metallic wedges for flatfoot correction to better understand their efficacy and safety. This systematic review adhered to PRISMA guidelines, and articles were searched in multiple databases (PubMED, SPORTDiscus, CINAHL, MEDLINE, and Web of Science) until August 2023 using a defined algorithm. Inclusion criteria encompassed midfoot surgeries using metallic wedges, observational studies, and English-language full-text articles. Data extraction, article quality assessment, and statistical analyses were performed. Among 11 included articles, a total of 444 patients were assessed. The average follow-up duration was 18 months. Radiographic outcomes demonstrated that patients who received metallic wedges experienced improvements in lateral calcaneal pitch angle and Meary’s angle, with an enhancement of up to 15.9 degrees reported in the latter. Success rates indicated superior outcomes for metallic wedges (99.3%) compared to bone allograft wedges (89.9%), while complications were generally minor, including hardware pain and misplacement. Notably, there were no infection complications due to the inert nature of the metallic elements. This review summarizes the effectiveness, success rates, and safety of metallic wedges for flatfoot correction. Radiographic improvements and high success rates highlight their efficacy. Minor complications, including pain and mispositioning, were reported, but the infection risk remained low. Our results demonstrate that metallic midfoot wedges may be a viable option over allograft wedges with proper planning. Future research should prioritize long-term studies and standardized measures.
]]>Biomechanics doi: 10.3390/biomechanics4010002
Authors: Pouyan Mehryar Mohammad Shourijeh Tahmineh Rezaeian Aminreza Khandan Neil Messenger Rory O’Connor Farzam Farahmand Abbas Dehghani-Sanij
Facing above-knee amputation poses a significant hurdle due to its profound impact on walking ability. To overcome this challenge, a complex adaptation strategy is necessary at the neuromuscular level to facilitate safe movement with a prosthesis. Prior research conducted on lower-limb amputees has shown a comparable amount of intricacy exhibited by the neurological system, regardless of the level of amputation and state of walking. This research investigated the differences in muscle synergies among individuals with unilateral transfemoral amputations during walking at three different speeds of transient-state gait. Surface electromyography was recorded from eleven male transfemoral amputees’ intact limbs (TFA), and the concatenated non-negative matrix factorization technique was used to identify muscle synergy components, synergy vectors (S), and activation coefficient profiles (C). Results showed varying levels of correlation across paired-speed comparisons in TFA, categorized as poor (S1), moderate (S3 and S4), and strong (S2). Statistically significant differences were observed in all activation coefficients except C3, particularly during the stance phase. This study can assist therapists in understanding muscle coordination in TFA during unsteady gait, contributing to rehabilitation programs for balance and mobility improvement, and designing myoelectric prosthetic systems to enhance their responsiveness to trips or falls.
]]>Biomechanics doi: 10.3390/biomechanics4010001
Authors: Luke Atkins Colin Coyle Jeremy Moody Rodrigo Ramirez-Campillo Paul J. Byrne
The aim of this study was to estimate the intra-day and inter-day reliability and usefulness of performance (Jump height (JH), ground contact time (GCT) and reactive strength index (RSI)), kinetic (force, power, eccentric rate of force development [E-RFD] and leg stiffness [LS]) and kinematic (velocity) variables during drop jumping (DJ) in hurling players. Seventeen (n = 17; mean ± SD; age = 23.35 ± 5.78 years, height = 178.35 ± 6.30 cm, body mass = 78.62 ± 8.06 kg) male club-level hurling players completed two maximal DJs from 0.20, 0.30, 0.40, 0.50 and 0.60 m drop heights on three testing days separated by 5–9 days of rest. Reliability was assessed using the coefficient of variation percentage (CV% ≤ 15%) and intraclass correlation coefficient (ICC > 0.70). For intra-day reliability, GCT (0.40 m, 0.50 m and 0.60 m), peak force (absolute and relative) (0.40 m and 0.50 m) and leg stiffness (0.40 m and 0.50 m) were found to be unreliable (ICC = 0.32–0.68 and CV% = 3.67–11.83%) from those specific drop heights. All other variables were found to be reliable (ICC = 0.72–0.98 and CV% = 1.07–14.02%) intra-day. All variables were found to be reliable (ICC = 0.72–0.96 and CV% = 2.57–14.68%) inter-day except for relative peak force and absolute and relative eccentric RFD (0.30 m and 0.40 m) (ICC = 0.68–0.90 and CV% = 7.76–16.47%). Practitioners have multiple reliable DJ performance, kinetic and kinematic variables for performance testing and training purposes.
]]>Biomechanics doi: 10.3390/biomechanics3040048
Authors: Akash Kalwar Mohsen Feyzi Reza Hashemi
This study aims to investigate the effect of ridged (micro-grooved) surface finish over the trunnion surface on the mechanics (stress, strain, and deformation) of the head–neck taper interface in hip implants. Using finite element modelling, the study focused on the geometric parameters of such micro-grooves to study how they would mechanically affect stress and deformation fields after the assembly procedure. As such, five different 2D models with varying micro-groove height and spacing were produced and assembled under an impaction assembly force of 4 kN in a 32 mm CoCrMo head engaged with a 12/14 Ti-6Al-4V neck. The results showed that lower von Mises stresses could be induced by either an increase or decrease in spacing against the base model (Model 1), which probably signifies that the relationship between the ridge spacing and stress may depend on the level of spacing. It was concluded that the geometrical parameters of the ridges (and their non-linear interactions) impact not only the stress and strain fields but also the assembly loading time at which the maximal stress and plastic deformation occur.
]]>Biomechanics doi: 10.3390/biomechanics3040047
Authors: Shota Enomoto Toshiaki Oda
We investigated the influence of Achilles tendon (AT) geometry on local-strain magnitude and distribution during loading, using finite element analysis. We calculated the following eight AT parameters for 18 healthy men: thickness and width of the most distal part, minimum cross-sectional area (mCSA), and most proximal part; length; and position of the mCSA. To investigate the effect of AT geometry on the magnitude and distribution of local strain, we created three-dimensional numerical models by changing the AT parameter values for every one standard deviation (SD) in the range of ±2 SD. A 4000 N lengthening force was applied to the proximal surface of all the models. The mean first principal strain (FPS) was determined every 3% of the length. The highest FPS in each model was mainly observed in the proximal regions; the 86–89% site (the most proximal site was set at 100%) had the highest number of models with the highest FPS (nine models). The highest FPS was observed in the model with a distal thickness of −2 SD, which was 27.1% higher than that of the standard model observed in the 2–5% site. Therefore, the AT geometry influences local-strain magnitude and distribution during loading.
]]>Biomechanics doi: 10.3390/biomechanics3040046
Authors: Bryon C. Applequist Zachary L. Motz Anastasia Kyvelidou
Background: Children’s gait is traditionally understood to mature as young as three years old through pre-adolescence. Studies looking at gait biomechanics suggest that gait matures around three years old, while studies investigating gait variability propose a much later maturation. The studies that have examined children’s gait variability did so while the children walked around a track or down hallways that created a discontinuous gait, potentially affecting the measures of variability and the efficacy of the results. Purpose: Therefore, the purpose of our study was to investigate the development of gait dynamics and gait variability in children in a more continuous fashion, in this case, by walking on a treadmill. Methods: To accomplish this, we included four age groups of children, ranging 2–10 years old, walking on a treadmill for at least three minutes while stride time and stride length were collected. Stride time and stride length’s variability was then analyzed using linear (mean, standard deviation, coefficient of variation) and nonlinear (sample entropy, detrended fluctuation analysis) measures across the varying ages of our participants. Results: Interestingly, both the linear and nonlinear variabilities of the stride time and stride length measures decreased as the groups of children got older. Specifically, CV ST (2–3 (9.3 ± 4%), 8–10 (3.6 ± 0.7%), p < 0.05) and CV SL (2–3 (11.4 ± 3%), 8–10 (4.6 ± 1%), p < 0.05) were our strongest linear measures, and DFA α ST (2–3 (0.97 ± 0.12), 8–10 (0.82 ± 0.10), p < 0.05) and DFA α SL (2–3 (0.91 ± 0.04), 8–10 (0.81 ± 0.03), p < 0.05) were our strongest nonlinear measures, particularly between the youngest and oldest groups. This trend of variability decreasing with age suggests that as children’s gait matures, their gait becomes more stable and reliable. Significance: Our study rejects the notion that children’s gait is mature by the age of three, as some would suggest. By analyzing the variability of stride time and stride length, we can see that even later into childhood, children’s gait continues to change and evolve.
]]>Biomechanics doi: 10.3390/biomechanics3040045
Authors: Gary Guerra John D. Smith Eun-Jung Yoon
Background: Agreement between the activities-specific balance confidence scale (ABC) and center of pressure (CoP) in prosthesis users is still very much unknown. The purpose of this study was to investigate the agreement between ABC and CoP in lower-limb prosthesis users. Methods: Twenty-one individuals with lower-limb prostheses were recruited. Participants were provided with the ABC scale and performed static balance tasks during eyes opened (EO) and eyes closed (EC) conditions whilst standing on a force platform. Pearson product moment coefficients between CoP displacements and ABC scores were performed. Participants were also stratified by those who had better (≥80 on ABC scale) and less (<80 on ABC scale) perceived balance confidence. Displacement was compared using an independent t-test with Cohen’s d to estimate effect size with alpha set at 0.05 for these tests. Results: There was a significant inverse moderate relationship between eyes opened displacement (EOD) (18.3 ± 12.5 cm) and ABC (75.1 ± 18.3%), r = (19)−0.58, p = 0.006, as well as eyes closed displacement (ECD) (37.7 ± 22.1 cm) and ABC, r = (19)−0.56, p = 0.008. No significant difference in EOD (t(19) = 1.36, p = 0.189, d = 0.61) and ECD (t(19) = 1.47, p = 0.156, d = 0.66) was seen between those with greater and less balance confidence. Conclusions: Self-report and performance-based balance outcome measures are recommended when assessing lower-limb prostheses users.
]]>Biomechanics doi: 10.3390/biomechanics3040044
Authors: Athanasios Gkrekidis Georgios Giarmatzis Dimitrios Menychtas Evangelos Karakasis Vassilios Gourgoulis Maria Michalopoulou Ilias Smilios Helen T. Douda Georgios Ch. Sirakoulis Nikolaos Aggelousis
This study validated muscle activation estimations generated by OpenSim during the gait of elderly fallers. Ten healthy elderly participants walked on an instrumented treadmill, monitored by motion capture, force platforms, and 12 surface EMG sensors. Static optimization was used to calculate muscle activations, evaluated through cosine similarity, comparing them with EMG signals from 12 muscles of the right leg. Findings revealed varied similarity levels across muscles and gait phases. During stance phase, tibialis anterior (TIBA), peroneus longus (PERL), soleus (SOL), gastrocnemius lateralis (GASL), semitendinosus (SEMI), tensor fasciae latae (TFL), and rectus femoris (RECF) demonstrated poor similarity (cosim < 0.6), while gluteus medius (GMED), biceps femoris long head (BFLH), and vastus lateralis (VL) exhibited moderate similarity (0.6 ≤ cosim ≤ 0.8), and gluteus maximus (GMAX) and vastus medialis (VASM) displayed high similarity (cosim > 0.8). During the swing phase, only SOL demonstrated inadequate similarity, while GASL, GMAX, GMED, BFLH, SEMI, TFL, RECF, and VASL exhibited moderate similarity, and TIBA, PERL, and VASM showed high similarity. Comparing the different 10% intervals of the gait cycle generally produced more favorable similarity results. For most of the muscles and intervals, good agreement was found. Moderate agreement was estimated in the cases of TIBA (0–10%), PERL (60–70%), GASL (60–70%), TFL (10–20%), RECF (0–10%, 80–100%), and GMED (50–60%). Bad agreement was found in the cases of SOL (60–70%), GASL (0–10%), and TFL (0–10%). In conclusion, the study’s validation outcomes were acceptable in most cases, underlining the potential for user-friendly musculoskeletal modeling routines to study muscle output during elderly gait.
]]>Biomechanics doi: 10.3390/biomechanics3040043
Authors: Hannah R. Freeman Harish Chander Sachini N. K. Kodithuwakku Arachchige Alana J. Turner J. Adam Jones Zhujun Pan Christopher Hudson Adam C. Knight
Background: Taking inspiration from the classical 1974, “moving room experiment” by Lee and Aronson, a “virtual moving room paradigm (Vroom)” was designed using virtual reality (VR) to assess postural control behavior. Methods: Thirty healthy adults (age: 21 ± 1 years; height: 166.5 ± 7.3 cm; mass: 71.7 ± 16.2 kg) were tested for postural stability in a virtual moving room paradigm (Vroom). The Vroom consisted of randomized virtual and visual perturbations of the virtual room moving toward and away from the individual, during both unexpected and expected trials. Objective postural sway variables and subjective experiences to VR using the simulator sickness questionnaire as well as balance confidence scale were also assessed and analyzed using a two way (2 × 2 [2 moving room direction (Toward vs. Away) and 2 knowledge of moving room (unexpected vs. expected)] repeated measures analysis of variance (ANOVA), and a one-way repeated measures ANOVA and paired sample t-test, respectively at an alpha level of 0.05. Results: Significantly greater postural sway was observed when the virtual room moved toward the participant than when moving away, and when it moved unexpectedly, compared with the expected moving room. Significantly improved balance confidence with realistic immersion and without simulator sickness was also observed. Conclusions: Our findings provide evidence indicating that the virtual moving room induces postural perturbations that challenge the postural control system, especially when the moving room is unexpected and moves toward the individual. Additionally, increased balance confidence and realistic immersion in the virtual environment with no adverse effects of simulator sickness were observed, providing evidence for the beneficial effects of the Vroom. Thus, the Vroom can be an easy and cost-effective method to expose individuals to realistic, virtual, and visual perturbations that challenge the postural control system and increase balance confidence, with realistic immersion and without adverse effects.
]]>Biomechanics doi: 10.3390/biomechanics3040042
Authors: Sanne Krakers Anil Peters Sybrand Homan Judith olde Heuvel Gabriëlle Tuijthof
Forefoot osteotomies to improve the alignment are difficult procedures and can lead to a variety of complications. Preoperative planning in three dimensions might assist in the successful management of forefoot deformities. The purpose of this study was to develop a global coordinate system in the foot for the planning of forefoot corrections. Two strategies (CS1 and CS2) were developed for defining a global coordinate system that meets the criteria of being well-defined, robust, highly repeatable, clinically relevant, compatible with foot CT scans, independent of the ankle joint angle, and does not include bones in the forefoot. The absolute angle of rotation was used to quantify repeatability. The anatomical planes of the coordinate systems were visually inspected by an orthopedic surgeon to evaluate the clinical relevancy. The repeatability of CS1 ranged from 0.48° to 5.86°. The definition of CS2 was fully automated and, therefore, had a perfect repeatability (0°). Clinically relevant anatomical planes were observed with CS2. In conclusion, this study presents an automated method for defining a global coordinate system in the foot according to predefined requirements for the planning of forefoot corrections.
]]>Biomechanics doi: 10.3390/biomechanics3040041
Authors: Nick Kampkuiper Jorm Nellensteijn Edsko Hekman Gabriëlle Tuijthof Steven Lankheet Maaike Koenrades Femke Schröder
Sacroiliac (SI) joint dysfunction can lead to debilitating pain but can be treated with minimally invasive sacroiliac joint fusion (SIJF). This treatment is commonly performed using 2D fluoroscopic guidance. This makes placing the implants without damaging surrounding neural structures challenging. Virtual surgical planning (VSP) using simulated fluoroscopic images may improve intraoperative guidance. This article describes a workflow with VSP in SIJF using simulated fluoroscopic images and evaluates achieved implant placement accuracy. Ten interventions were performed on 10 patients by the same surgeon, resulting in a total of 30 implants; the median age was 39 years, and all patients were female. The overall mean implant placement accuracy was 4.9 ± 1.26 mm and 4.0 ± 1.44°. There were no malpositioning complications. VSP helped the surgeon understand the anatomy and determine the optimal position and length of the implants. The planned positions of the implants could be reproduced in surgery with what appears to be a clinically acceptable level of accuracy.
]]>Biomechanics doi: 10.3390/biomechanics3040040
Authors: Lucas Galey Guillermo Beckmann Ethan Ramos Frances A. Rangel Roger V. Gonzalez
Approximately 82% of amputees prefer microprocessor knees (MPKs) to the passive alternatives. However, the cost of these devices makes them inaccessible for many patients. The aim of this research is to develop an affordable MPK that allows for stumble reduction and flexion dampening at a fraction of the cost of similar devices. The GKnee was developed by a sophisticated mathematical model that can effectively calculate geometric configuration and simulate forces transferred through a prosthetic knee at any given point through the gait cycle. With a median error of 6%, the mathematical model was developed to the point of reasonable accuracy for determining component placement and force interactions. The model served as a valuable tool to assist in the iterative design process of the GKnee, influencing component selection for the hydraulic system and frame design. This model was then validated using a compression rig and a mock GKnee prototype. The GKnee was then evaluated for its ability to perform under expected loading conditions, using compression testing and dynamic flexion testing. This research led to the development of a sub USD 500 microprocessor prosthetic, while remaining under 2.27 kg.
]]>Biomechanics doi: 10.3390/biomechanics3040039
Authors: Víctor Hernández-Beltrán Mário C. Espada Jesús Muñoz-Jiménez Kiko León Cátia C. Ferreira Jose A. Parraca José M. Gamonales
Biomechanical analysis has been one of the most used procedures when aiming to improve performance in sports and is also very relevant and decisive in the final classification of competitive events in sports such as gymnastics. Hence, this study sought to provide an overview of the number of scientific literature publications related to biomechanics research in gymnastics. The document search was completed in March 2023 and reflected a bibliometric analysis considering the published manuscripts up to 31 December 2022. Data collection was performed on the Web of Science, following the bibliometric analysis law, using Microsoft Excel and VosViewer Software (v1.6.19) for analysis and data processing. A total of 325 documents related to the topic under study were located. The results highlight that the older manuscripts date from 1980, with a growing trend of publications from that moment until now and a very visible increase in 2015, and that Sport Science is the category associated with more published manuscripts. A total of 30 manuscripts have 30 or more citations, 746 authors and co-authors are associated with the publications, and 58 co-authorships have published one or more studies. Moreover, 47 countries or regions have been associated with the topic under study, with the USA, England, and Australia being the countries with the most published articles and citations. The study also found that the highest frequency keywords are: “gymnastics” (n = 122), “biomechanics” (n = 73), “simulation” (n = 27), and “performance” (n = 25), considering the average year of publication of the documents, “balance” (n = 11), “artistic gymnastic” (n = 14) and “training” (n = 25) are the most frequently used terms. This study reveals that the topic of biomechanics in gymnastics has shown sustained growth and deserves the attention of the scientific community, but at the same time, there is still much room for research development.
]]>Biomechanics doi: 10.3390/biomechanics3040038
Authors: Jordi Arboix-Alió Guillem Trabal Dani Moreno-Galcerán
This study aimed to report the shooting velocities and to assess the differences in shot velocity according to the techniques used in elite youth male rink hockey players. Fifteen rink hockey players (age = 18.40 ± 1.44 year; body mass = 73.52 ± 6.02 kg; height = 1.76 ± 0.06 m; BMI = 23.61 ± 2.12; sports experience = 6.44 ± 1.76 years) participated in this cross-sectional study. Shooting velocities were assessed for four techniques: slap shot without approach run, drive shot without approach run, slap shot with approach run, and drive shot with approach run. Shooting velocity measurements were conducted using a radar Stalker ATS systemTM. The results demonstrated that drive shots consistently achieved higher velocities compared to slap shots (F(3,56) = 23.9 p < 0.01, ηp2 = 0.58). Additionally, incorporating an approach run significantly increased shooting velocities for both techniques (p < 0.01). These findings hold significant implications for coaches and players seeking to optimize shooting performance in rink hockey.
]]>Biomechanics doi: 10.3390/biomechanics3040037
Authors: Isaura Leite Márcio Goethel Filipe Conceição Lurdes Ávila-Carvalho
An increased jumping performance is key for gymnastics competition routines. Rhythmic gymnasts (RGs) use the jump as one of the main body elements. In Acrobatic Gymnastics (ACRO), top gymnasts must coordinate their jumps with the impulse provided by base gymnast(s). It is expected that the gymnasts’ discipline and role played impact their jumping skill. This work aims to investigate how the jumping performance differs between ACRO gymnasts and RGs, focusing on the Force–Velocity (F-V) profile mechanical variables. Gymnasts were divided in three groups: ACRO tops (n = 10, 13.89 (3.62) median (interquartile interval) years old), ACRO bases (n = 18, 18.24 (4.41) years old) and RGs (n = 15, 12.00 (3.00) years old). The F-V profile during countermovement jump and its mechanical variables were evaluated using MyJump2. A training background survey and anthropometric assessments were conducted. The significance level was set at p ≤ 0.05. Group comparisons showed that ACRO bases jump higher than ACRO tops and RGs, present a higher maximal force than RGs and a more balanced F-V profile, while RGs present high force deficits. Coaches can use this data to develop interventions that optimize the training stimulus to different gymnastics disciplines considering the individual characteristics and adaptability of each gymnast.
]]>Biomechanics doi: 10.3390/biomechanics3040036
Authors: Albert T. Anastasio Anthony N. Baumann Andrew Fiorentino Katelyn Sidloski Kempland C. Walley Aditya Muralidharan Keegan T. Conry Jacob C. Hoffmann
Cervical disc degenerative disease (CDDD) is a common spinal pathology that is often treated with anterior cervical discectomy and fusion (ACDF), cervical disc arthroplasty (CDA), and/or hybrid cervical surgery (HCS). The purpose of this first-time systematic review is to examine the biomechanical outcomes associated with three types of non-contiguous cervical surgeries—ACDF, CDA, and HCS—to provide a greater understanding of non-contiguous cervical surgical biomechanics. A systematic review was performed using PubMed, Cumulated Index to Nursing and Allied Health Literature (CINAHL), MEDLINE, and Web of Science from database inception until June 6th, 2023. The inclusion criteria was any article that reported biomechanical or kinematic outcomes, outcomes for any of the three non-contiguous cervical surgeries, and human-derived and/or human cadaver subjects. A total of 5 biomechanical articles were included from a total of 523 articles. Non-contiguous two-level HCS experienced less drastic range-of-motion (ROM) changes throughout the cervical spine and decreased intervertebral disc pressure (IDP) compared to non-contiguous two-level ACDF. Non-contiguous two-level CDA resulted in more cervical ROM and less non-operative segment facet contact force compared to non-contiguous two level ACDF. There was less cephalad and caudal non-operative segment ROM in non-contiguous two-level ACDF compared to contiguous three-level ACDF.
]]>Biomechanics doi: 10.3390/biomechanics3030035
Authors: Raviraj Nataraj Sean Patrick Sanford Mingxiao Liu
This study examined the effects of different modes of augmented visual feedback of joint kinematics on the emerging joint moment patterns during the two-legged squat maneuver. Training with augmented visual feedback supports improved kinematic performance of maneuvers related to sports or daily activities. Despite being representative of intrinsic motor actions, joint moments are not traditionally evaluated with kinematic feedback training. Furthermore, stabilizing joint moment patterns with physical training is beneficial to rehabilitating joint-level function (e.g., targeted strengthening and conditioning of muscles articulating that joint). Participants were presented with different modes of augmented visual feedback to track a target squat-motion trajectory. The feedback modes varied along features of complexity (i.e., number of segment trajectories shown) and body representation (i.e., trajectories shown as sinusoids versus dynamic stick-figure avatars). Our results indicated that mean values and variability (trial-to-trial standard deviations) of joint moments are significantly (p < 0.05) altered depending on the visual feedback features being applied, the specific joint (ankle, knee, hip), and the squat movement phase (early, middle, or late time window). This study should incentivize more optimal delivery of visual guidance during rehabilitative training with computerized interfaces (e.g., virtual reality).
]]>Biomechanics doi: 10.3390/biomechanics3030034
Authors: Márcio Fagundes Goethel João Paulo Vilas-Boas Leandro Machado Ulysses Fernandes Ervilha Pedro Vieira Sarmet Moreira Antonio Roberto Bendilatti Joseph Hamill Adalgiso Coscrato Cardozo Mauro Gonçalves
This study aimed to investigate and compare the performance, perceptual and reaction skills and neuromuscular control indicators of sub-elite (SEG) and elite (EG) karate athletes during the execution of a Gyaku Tsuki punch. The study included 14 male athletes, equally divided into two subgroups according to their current competitive level. We analyzed the peak and mean linear velocity of the wrist, linear peak acceleration/deceleration of the wrist, braking time, pre-motor time, motor time, reaction time, movement time and co-contraction index between selected muscle groups. EG athletes presented higher values in almost all performance variables, with the exception of the mean linear velocity of the wrist, which was similar between the groups. In the perceptual and reaction skills, the EG athletes presented shorter time durations with the exception of the pre-motor time, which did not reveal significant differences. The only significant difference in the indicators of neuromuscular control were found during the deceleration phase, where the EG athletes presented a higher co-contraction index between the biceps brachii and the triceps brachii. In conclusion, the EG athletes, in addition to being faster to react, faster to accelerate the wrist, could perform the braking in less time than the SEG athletes, making the technique less perceptible to the opponent.
]]>Biomechanics doi: 10.3390/biomechanics3030033
Authors: Nick van der Geest Lorenzo Garcia
Sea turtles are a keystone species for the ocean’s ecosystem, with all species currently being listed as endangered. Such a threat is mainly due to human factors such as fishing net entanglement. This entanglement often comes at the expense of turtles losing a pectoral flipper. The reduction in a sea turtle’s survival odds upon losing a flipper is a significant concern. This issue extends beyond individual animals, as the potential extinction of sea turtles could have detrimental effects on ocean health and subsequently disrupt our lifestyles. In this work, with the help of robotics, we tested the suitability of a prosthetic flipper for sea turtles that have lost a flipper. Testing with our sea-turtle-inspired robot helped to demonstrate the prosthetic flipper’s performance without clinical trials in live animals. The robot showed that the prosthetic could closely mimic the sea turtle’s downstroke and upstroke, allowing the animal to regain control in roll, pitch, and yaw, despite the absence of anatomical joints and related muscles. Additionally, swim speed tests provided an average swim speed of 0.487 m/s while dragging 6 m of cable to give a calculated maximum swim speed of 0.618 m/s, coming close to the average swim speed of wild sea turtles of 0.6 m/s. Our aspiration is that the findings from this study will pave the way for an open-source implant design, empowering veterinary professionals globally to aid injured turtles. Furthermore, this research promises to inspire additional animal-based robotic designs, advancing technologies geared towards assisting other animals in distress.
]]>Biomechanics doi: 10.3390/biomechanics3030032
Authors: Vasiliki Chaitidou Vassilios Panoutsakopoulos
The aim of the study was to examine the inter-limb asymmetry in force application in a 1-s maximum isometric leg press test (ISOM) and vertical jump tests without an arm swing (VJ)of male long jumpers. Nine experienced jumpers (age: 18–30 y, LJ personal best: 6.50–8.05 m) were examined. Participants performed: (a) bilateral VJs from the squatting position (SQJ) and with a countermovement (CMJ), (b) unilateral CMJ from the take-off (TOL) and swing (SWL) leg used in the LJ take-off, and c) bilateral 1-s ISOM tests. Data were collected for each lower limb with separate force dynamometers (sampling frequency: VJs = 1 kHz, ISOM = 500 Hz). The inter-limb asymmetry of the peak applied force was evaluated using the symmetry angle. The paired samples T-test revealed non-significant (p > 0.05) inter-limb differences for the force output in the bilateral jump tests, in the unilateral jump tests, and in the ISOM. In conclusion, despite the fact that a powerful unilateral take-off is required for the optimization of long jump performance, no asymmetry was found in the examined tests, suggesting that the dominant/take-off leg was not stronger than the contra-lateral leg. This is possibly due to the intensive execution of other bilateral tasks involved, like the approach run.
]]>Biomechanics doi: 10.3390/biomechanics3030031
Authors: Kenta Chida Takayuki Inami Shota Yamaguchi Yasumasa Yoshida Naohiko Kohtake
We investigated the influence of advance lunging in fencing from the perspective of velocity and lower limb joint angles to identify how the joint angles contribute to the peak velocity in a lunge with advance (LWA). Fourteen skilled athletes (age: 19.6 ± 0.9 years, height: 171.2 cm ± 5.2 cm, weight: 63.7 kg ± 5.3 kg, and fencing experience: 9.7 ± 3.1 years) participated by performing two types of attacking movements, and data were collected with a 3D movement analysis system. A correlation between the peak velocity of the body center of mass (CoM) in an advance lunge and several joint angle variables (rear hip peak flexion angle (r = 0.63), rear ankle peak dorsiflexion angle (r = −0.66), rear ankle range of motion (r = −0.59), and front hip peak extension angle (r = 0.54)) was revealed. In addition, the joint angle variables that significantly predicted peak CoM velocity during an LWA were the rear knee peak flexion angle (β = 0.542), rear knee peak extension angle (β = −0.537), and front knee peak extension angle (β = −0.460). Our findings suggest that the rear leg hip joint, rear leg ankle joint, and front leg hip joint may control the acceleration generated by an LWA. Furthermore, more flexion of the rear leg knee joint in the early phase of the lunge and greater extension of the rear and front leg knee joints at the end of the lunge phase may help increase peak velocity.
]]>Biomechanics doi: 10.3390/biomechanics3030030
Authors: Giacomo Farì Francesca Latino Francesco Tafuri Laura Dell’Anna Maria Vittoria Raele Annatonia Fai Carlo De Serio Giorgia Intonti Anna Lisa De Salvo Vincenzo Ricci Emma Saraiello Valerio Bonavolontà Andrea Bernetti Silvia Fiore Marisa Megna Maurizio Ranieri
Wheelchair basketball (WB) is an increasingly popular sport that guarantees numerous health benefits for people with disabilities who regularly practice it, such as an improved quality of life and psychophysical well-being. However, WB is a contact and high-stress sport, which exposes players to frequent overloads and injuries, mainly affecting the upper limbs. Therefore, shoulder pain (SP) is the most common musculoskeletal disorder among WB players, forcing them to suspend or abandon this sport activity. This narrative review aims to summarize all the known literature on this topic and to be a starting point for further research. Firstly, it explores the biomechanical causes that lead to SP and the underlying diseases, among which the most recurrent are rotator cuff tendinopathies. Furthermore, this overview deepens the most effective and specific rehabilitation programs for SP in WB players and it emphasizes the need for further studies to trial new rehabilitative protocols using novel technologies to make them faster and more personalized. In this regard, the general recommendation still remains to perform a combination of exercises such as strengthening, endurance and stretching exercises of various durations and intensities. To conclude, the most important prevention strategies are described, underlining the need for constant sport-specific training led by qualified personnel and suggesting some insights on possible new research aimed at improving wheelchair ergonomics, stressing the importance of a multidisciplinary team fully dedicated to the individual athlete.
]]>Biomechanics doi: 10.3390/biomechanics3030029
Authors: Robert Graydon Alison J. Northrop Jaime H. Martin Mark Lucey Johannes Peter Schramel Christian Peham Lars Roepstorff Jonathan Sinclair Sarah Jane Hobbs
The ground has long been cited as a key contributing factor for injury risk in the cross-country phase of eventing. The current study aimed to develop a practically useful standardized protocol for measuring eventing cross country ground. Data collection was split into three phases: Phase 1 (Validation), Phase 2 (Expansion of data set), and Phase 3 (Threshold establishment). During Phase 1, data from nine event courses were collected using an Orono Biomechanical Surface Tester (OBST), Vienna Surface Tester (VST), Lang Penetrometer, Going Stick, and moisture meter. Using linear regression, 80% of the variability in cushioning measured with the OBST was predicted from moisture and VST measurements (p < 0.001). In Phase 2, objective data from 81 event courses and subjective assessments from 180 event riders were collected. In Phase 3, k-means cluster analysis was used to classify the courses into ten clusters based on average course measurements of moisture, cushioning, firmness, stiffness, depth, and coefficient of restitution. Based on cluster membership, course average subjective data (16 courses) were compared using a General Linear Model. Significant differences (p < 0.05) in subjective impact firmness (p = 0.038) and subjective cushioning (p = 0.010) were found between clusters. These data and cluster thresholds provide an event course baseline for future comparisons.
]]>Biomechanics doi: 10.3390/biomechanics3030028
Authors: Grace Hey Matthew Willman Aashay Patel Michael Goutnik Jonathan Willman Brandon Lucke-Wold
Spinal cord injury (SCI) is a profoundly debilitating yet common central nervous system condition resulting in significant morbidity and mortality rates. Major causes of SCI encompass traumatic incidences such as motor vehicle accidents, falls, and sports injuries. Present treatment strategies for SCI aim to improve and enhance neurologic functionality. The ability for neural stem cells (NSCs) to differentiate into diverse neural and glial cell precursors has stimulated the investigation of stem cell scaffolds as potential therapeutics for SCI. Various scaffolding modalities including composite materials, natural polymers, synthetic polymers, and hydrogels have been explored. However, most trials remain largely in the preclinical stage, emphasizing the need to further develop and refine these treatment strategies before clinical implementation. In this review, we delve into the physiological processes that underpin NSC differentiation, including substrates and signaling pathways required for axonal regrowth post-injury, and provide an overview of current and emerging stem cell scaffolding platforms for SCI.
]]>Biomechanics doi: 10.3390/biomechanics3030027
Authors: Jeffrey Buxton Kelly J. Shields Holyna Nhean Jared Ramsey Christopher Adams George A. Richards
Fatigue-related changes in gait biomechanics, specifically plantar pressures, are well documented in the general population. However, research is generally confined to unilateral measures across a limited range of speeds, while changes in more well-trained populations remain largely unknown. Therefore, we sought to assess the impact of fatigue on bilateral peak plantar pressure (PP) and plantar pressure symmetry angle (SA) in well-trained runners across a range of speeds. Data from 16 (females, n = 9) well-trained runners were collected using in-sole pressure sensors pre- and post-fatigue at the following speeds: walking (1.3 m/s), jogging (2.7 m/s), running (3.3 m/s), and sprinting (4.5 m/s). Pre-fatigue PP significantly increased from walking to jogging (p < 0.001) and from jogging to running (p < 0.005) with no difference between running and sprinting (p > 0.05). Post-fatigue PP for walking was less than jogging (p < 0.002), running (p < 0.001), and sprinting (p < 0.001), with no other significant differences (p > 0.05). Post-fatigue PP was significantly greater when compared to pre-fatigue PP at all speeds (p < 0.001 for all). Though SA was not significantly different pre- to post-fatigue across speeds (p’s > 0.05) at the cohort level, noteworthy changes were observed at the individual level. Overall, fatigue effects are present at all running speeds but isolating these effects to a single side (left or right) may be inadequate.
]]>Biomechanics doi: 10.3390/biomechanics3030026
Authors: Nicolas M. Philipp Dimitrije Cabarkapa Kennedy M. Marten Damjana V. Cabarkapa Dragan M. Mirkov Olivera M. Knezevic Jelena Aleksic Lucija Faj Andrew C. Fry
Given the multidirectional nature of the sport, handball athletes must frequently perform high-intensity decelerations to avoid defenders, generate space, or perform directional changes. The aim of the present study was twofold: (i) to investigate different kinematic measures of horizontal deceleration performance by comparing the acceleration-deceleration assessment (ADA) with the 5-0-5 test and (ii) to investigate relationships between force-time characteristics derived from the countermovement vertical jump (CVJ) and measures of horizontal deceleration performance. Eleven female handball players competing in the first-tier professional league in Europe performed three CVJs while standing on a uni-axial force plate system sampling at 1000 Hz, followed by two ADAs (i.e., maximal-effort acceleration over a 10 m distance, followed by rapid deceleration) and 5-0-5 test trials. Tripod-mounted radar sampling at 47 Hz, placed 5 m behind the start line, was used to record horizontal velocity data. Each test was separated by a 5–7 min rest interval to minimize the influence of fatigue. No statistically significant differences were found in horizontal deceleration performance parameters between ADA and the 5-0-5 test. However, athletes with a higher CVJ height and reactive strength index-modified showed better performance in terms of horizontal deceleration measures such as maximal approach velocity and average and maximal deceleration. Overall, these results may be of interest to practitioners working with multidirectional sport athletes such as handball players as they provide critical insight for the selection of assessments and training strategies targeted toward optimizing on-court athlete performance.
]]>Biomechanics doi: 10.3390/biomechanics3030025
Authors: Joey O. Brien Declan Browne Des Earls Clare Lodge
The main aim of this study was to examine the relationship between body weight, absolute and relative strength and power variables in a flywheel Romanian deadlift. A secondary aim was to assess the inter-day reliability of a novel power assessment protocol previously used to determine the inertial load that produced the maximum power output in Flywheel Inertia Training. Ten physically active males took part in this study. Participants had some experience with flywheel devices, but all had a minimum of 24 months of traditional resistance training experience. The first testing session consisted of three sets of 10 repetitions with a different inertial load for each set (0.050, 0.075, and 1.00 kg·m2). Each set’s first and second repetitions were used to build momentum and were excluded from data analysis. The order of inertial load used in each trial was standardized for all participants: first, 0.050 kg·m2, second, 0.075 kg·m2, and last, 0.100 kg·m2. The secondary testing session followed the same procedure as the first. No statistically significant (p < 0.05) effect was found between any of the variables in the correlation analysis. There were large positive correlations between the 1 repetition max flywheel Romanian deadlift and peak concentric power, relative strength, and peak concentric and eccentric peak powers. Both body weight and relative strength showed moderate negative correlations with % eccentric overload, whereas moderate positive correlations were observed between 1RM and peak eccentric power. Both concentric power and eccentric power showed excellent reliability, while the reliability for % eccentric overload ranged from poor to excellent depending on the inertial load. In conclusion, this study shows that a protocol to assess the maximum power output has excellent reliability for both ECC and CON power and may be used in future flywheel training. The results also showed that body weight, maximum strength, and relative strength were not largely related to power variables. An individualized approach to flywheel training is required.
]]>Biomechanics doi: 10.3390/biomechanics3030024
Authors: Sarah Aruje Zahid Yunus Celik Alan Godfrey John G. Buckley
Normal ankle function provides a key contribution to everyday activities, particularly step/stair ascent and descent, where many falls occur. The rising to up-on-the-toes (UTT) 30 second test (UTT-30) is used in the clinical assessment of ankle muscle strength/function and endurance and is typically assessed by an observer counting the UTT movement completed. The aims of this study are: (i) to determine whether inertial measurement units (IMUs) provide valid assessment of the UTT-30 by comparing IMU-derived metrics with those from a force-platform (FP), and (ii) to describe how IMUs can be used to provide valid assessment of the movement dynamics/stability when performing a single UTT movement that is held for 5 s (UTT-stand). Twenty adults (26.2 ± 7.7 years) performed a UTT-30 and a UTT-stand on a force-platform with IMUs attached to each foot and the lumbar spine. We evaluate the agreement/association between IMU measures and measures determined from the FP. For UTT-30, IMU analysis of peaks in plantarflexion velocity and in FP’s centre of pressure (CoP) velocity was used to identify each repeated UTT movement and provided an objective means to discount any UTT movements that were not completed ‘fully’. UTT movements that were deemed to have not been completed ‘fully’ were those that yielded peak plantarflexion and CoP velocity values during the period of rising to up-on-the-toes that were below 1 SD of each participant’s mean peak rising velocity across their repeated UTT. The number of UTT movements detected by the IMU approach (23.5) agreed with the number determined by the FP (23.6), and each approach determined the same number of ‘fully’ completed movements (IMU, 19.9; FP, 19.7). For UTT-stand, IMU-derived movement dynamics/postural stability were moderately-to-strongly correlated with measures derived from the FP. Our findings highlight that the use of IMUs can provide valid assessment of UTT test(s).
]]>Biomechanics doi: 10.3390/biomechanics3020023
Authors: Arash Bagheri Keith Alexander
Background: The aging process contributes to the decline in physical capacity that leads to loss of independence in performing life activities. Immobility and instability are the most significant predictors and indicators of physical disability and dependence. As a result, a variety of assistive devices exist to address immobility and instability in older adults, including walkers, canes, crutches, wheelchairs and handrails. Sit-to-stand (STS) transitions are the most common transitions in daily mobility activities. The ability to perform STS transitions successfully is therefore one of the most important activities to focus attention on. As a result of physical deterioration, older adults will sooner or later be faced with their physical limitations, and in particular, will not be able to provide enough torque at critical body joints to make the STS transition. Aim: This paper suggests employing two-arm assistance using two handles located symmetrically in the body’s sagittal plane. During the aging process, people are faced with varying levels of muscle deterioration and body constraints and consequently require different levels of assistance to complete the transition successfully. This paper aims to develop a tool to find the optimum handle location for people based on their body constraints to reduce knee torque (identified as the critical joint in the STS transition). These findings are also used to measure the effects of assistive device handle position on the biomechanics of the two-arm assisted STS transition. Methods: For this purpose, a theoretical tool was developed by integrating human body kinetics with a multi-objective genetic algorithm to find the optimum hand force required at the seat-off point for a set of potential handle locations. The tool was set to achieve the minimum knee torque within the defined body constraints and assumptions. In line with the physics of the STS transition, the “seat-off point”, when subjects lose their seat support, was chosen as the most challenging point of the task. This was coupled with the “nose over toes” posture recommended to older adults by occupational therapists. Results and Discussion: The schematic of the developed tool shows that the best handle locations requiring the minimum torques at the body joints are positioned in handle zone 2, where the handles are placed vertically above the knee and below the hip joints and horizontally located ahead of the hip and behind the knee joints. Within this handle zone, both components of the hand forces (vertical downward and horizontal backward) provide assisting torque to all the body joints and consequently reduce the torques required at body joints.
]]>Biomechanics doi: 10.3390/biomechanics3020022
Authors: Hallvard Nygaard Falch Eirik Kristiansen Roland van den Tillaar
When performing the traditional barbell back squat, athletes may experience discomfort in the shoulders or be limited by shoulder mobility. The Squatbar® is a barbell designed to be ergonomic to the shoulders but has never, in the scientific literature, been compared to the traditional Olympic barbell. Thus, the current study investigated kinematics, kinetics, and myoelectric activity (EMG) between the Squatbar® barbell and the Olympic barbell when performing a one-repetition maximum (1-RM) back squat. Twelve strength-trained men (body mass: 83.5 ± 7.8 kg, age: 27.3 ± 3.8 years, height: 180.3 ± 6.7 cm) performed a 1-RM squat with both the Olympic and Squatbar® barbells. The paired samples t-test revealed significantly more weight was lifted with the Olympic barbell compared to the Squatbar® barbell (148 ± 21 kg vs. 144.5 ± 20 kg) and was accompanied by greater shoulder external rotation (74 ± 7.5° vs. 59.6 ± 9.2°). No differences in joint kinematics of the lower limbs, kinetics, or EMG were observed between the two barbells. The results of the current study indicate the Squatbar® to be a suitable substitution for the Olympic barbell for athletes with reduced shoulder mobility when performing the squat. It was concluded that the Squatbar® induces similar kinetics, kinematics, and EMG when compared to the Olympic barbell, except for reducing external rotation of the shoulder.
]]>Biomechanics doi: 10.3390/biomechanics3020021
Authors: Aki-Matti Alanen Lauren C. Benson Matthew J. Jordan Reed Ferber Kati Pasanen
The aim of this study was to assess center of mass (COM) acceleration and movement during change of direction (COD) maneuvers during a competitive soccer game to elucidate situation-specific demands of COD performance. This information can assist in developing soccer-specific tests and training methods. Fifteen elite-level female youth soccer players were tracked for one game with inertial measurement units (IMU) attached to the lower back. COD movements in combination with situational patterns were identified using high-speed video. LASSO regression was used to identify the most important predictors associated with higher vertical peak accelerations (PAv) of the COM during COD movements. COD angle, running speed, contact, and challenge from the opposition were identified as important features related to higher PAv. This study adds to the literature on the demands of COD performance in soccer match-play. The unique approach with game-specific situational data from female youth players provides increased insight into the game-demands of COD and agility performance. PAv in games was higher with larger COD angles, increased running speed, or with contact when the player was challenged by the opposition. A larger study including more games is warranted to increase confidence in using these variables as a basis for training or testing agility.
]]>Biomechanics doi: 10.3390/biomechanics3020020
Authors: Joshua P. McGeown Mangor Pedersen Patria A. Hume Alice Theadom Stephen Kara Brian Russell
Although injury mechanisms of mild traumatic brain injury (mTBI) may be similar across patients, it is becoming increasingly clear that patients cannot be treated as one homogenous group. Several predominant symptom clusters (PSC) have been identified, each requiring specific and individualised treatment plans. However, objective methods to support these clinical decisions are lacking. This pilot study explored whether wearable sensor data collected during the Buffalo Concussion Treadmill Test (BCTT) combined with a deep learning approach could accurately classify mTBI patients with physiological PSC versus vestibulo-ocular PSC. A cross-sectional design evaluated a convolutional neural network model trained with electrocardiography (ECG) and accelerometry data. With a leave-one-out approach, this model classified 11 of 12 (92%) patients with physiological PSC and 3 of 5 (60%) patients with vestibulo-ocular PSC. The same classification accuracy was observed in a model only using accelerometry data. Our pilot results suggest that adding wearable sensors during clinical tests like the BCTT, combined with deep learning models, may have the utility to assist management decisions for mTBI patients in the future. We reiterate that more validation is needed to replicate the current results.
]]>Biomechanics doi: 10.3390/biomechanics3020019
Authors: Chun-Hao Huang Burcu Aydemir Kharma C. Foucher
We have shown that step length asymmetry seen in hip osteoarthritis (OA) is associated with poorer mechanical energy exchange and higher metabolic cost. Thus, we conducted this proof-of-concept study to investigate whether modifying step length through split-belt treadmill training can improve walking energetics. We conducted split-belt treadmill training in four periods with simultaneous motion and metabolic analyses in 10 women with unilateral hip OA. Using repeated measures ANOVA, we evaluated changes across each period, in step length asymmetry, mechanical energy exchange, and O2 rate. We also examined changes in hip range of motion and peak plantarflexor moment. We used Spearman correlations (rho) to assess the strength of associations between variables at baseline and after adaptation. We found that step length asymmetry and O2 rate decreased (p = 0.007, p < 0.001) and mechanical energy exchange increased (p < 0.001). Reduced step length asymmetry was associated with reduced O2 rate (rho = 0.732, p = 0.016). Hip range of motion increased (p < 0.001) and was associated with decreased step length asymmetry (rho = 0.818, p = 0.004), indicating a potential mechanism. These findings suggest that reducing step length asymmetry by split-belt treadmill training could improve walking energetics in hip OA people.
]]>Biomechanics doi: 10.3390/biomechanics3020018
Authors: Vassilios Panoutsakopoulos Iraklis A. Kollias
The inability to control the body center of mass (BCM) initial conditions, when executing plyometric exercises, comprises a restrictive factor to accurately compare jumps executed vertically and horizontally. The purpose of the study was to present a methodological approach for the examination of BCM initial conditions during vertical drop jumps (VDJ) and plyometric rebound jumps performed with a pendulum swing (HPRJ). A system consisting of two force plates was used for the evaluation of VDJ. A bifilar pendulum, equipped with a goniometer and accelerometer, was constructed for the evaluation of the HPRJ. Kinematic parameters from both jump modalities were obtained by means of videography (100 Hz). Thirty-eight physically active young males executed VDJ and HPRJ with identical BCM kinetic energy at the instant of impact (KEI). Results revealed that participants produced higher power and lower force outputs at HPRJ (p < 0.01). The rate of force development was larger in VDJ, while hip movement was less in HPRJ. The use of the presented methodology provided the means to reliably determine the exact BCM release height during the execution of the examined jumps. This provided an accurate determination of the amount of KEI, being the main parameter of calculating load during plyometric exercise.
]]>Biomechanics doi: 10.3390/biomechanics3020017
Authors: Hiroki Hyodo Daiki Koga Yasuo Sengoku Tadashi Wada
This study aimed to estimate the trunk twist angle from the shoulder and hip rotation angles in short-distance crawl swimming and to elucidate the twist motion of the relationship between the trunk and the rotation angular velocity in response to changes in swimming speed. Swimming speed during the experimental trials was computed from the subject’s best times in the 50 and 100 m crawl swims. Wireless self-luminous LED markers were attached to seven locations on the body. The actual coordinate values of the LED markers were obtained using 18 cameras for underwater movements and 4 on the water for above-water movements. A comparison of the rate of change between trials revealed a high correlation (r = 0.722, p < 0.01) between the twist angle and shoulder rotation angular velocity in the Push phase. In the same phase, a high correlation (r = 0.748, p < 0.01) was also found between the twist angle and the angular velocity of hip rotation. These results suggest that swimmers increase the twist angle of their trunks to obtain a higher swimming speed.
]]>Biomechanics doi: 10.3390/biomechanics3020016
Authors: Paul A. Jones Ali Rai Thomas Dos’Santos Lee C. Herrington
Background: The cutting movement assessment score (CMAS) provides a qualitative assessment of the side-step cutting (S-SC) technique. Previous research has been undertaken primarily by biomechanists experienced with S-SC evaluations. Little is known about the agreement between various sports science and medicine practitioners to ascertain whether the tool can be used effectively by different practitioners in the field. Currently, the CMAS uses three camera views (CVS) to undertake the evaluation, and it would be worthwhile to know whether the CMAS can be effectively conducted with fewer camera views to improve clinical utility. Therefore, the aim of the study was to examine the inter-rater agreement between different sports science and medicine practitioners and agreement between using different CVS to evaluate the S-SC technique using the CMAS. Methods: Video data were collected from 12 male rugby union players performing a 45° S-SC manoeuvre toward both the left and right directions. Five different sports science and medicine practitioners evaluated footage from three cameras of one left and one right trial from each player using the CMAS. Twelve different trials were also evaluated by the sports rehabilitator using single and multiple CVS. Agreements (percentage; Kappa coefficients (K)) between different practitioners and configurations of the CVS were explored. Results: Good to excellent inter-rater agreements were found between all practitioners for total score (K = 0.63–0.84), with moderate to excellent inter-rater agreements observed across all items of the CMAS (K = 0.5–1.0). Excellent agreement was found between using three CVS vs. two CVS that included at least a sagittal view (K = 0.96–0.97). Lower agreement (K = 0.83) was found between angle-frontal views with three CVS. Conclusions: The CMAS can be used effectively by various practitioners to evaluate the movement quality of S-SC. The use of two CVS that include at least a sagittal plane view would suffice to evaluate the S-SC technique against the CMAS.
]]>Biomechanics doi: 10.3390/biomechanics3020015
Authors: Ivanna Kramer Sabine Bauer Valentin Keppler
In many fields of spinal health care, efforts have been made to offer individualized products and therapy tailored to the patient. Therefore, the prevailing alignment of the spine must be considered, which varies from person to person and depends on the movement and loading situation. With the help of patient-specific simulation models of the spine, the geometrical parameters in a specific body position can be analyzed, and the load situation of the spinal structures during dynamic processes can be assessed. However, to enable the future usability of such simulation models in medical reality, as many patient-specific conditions as possible need to be considered. Another critical requirement is that simulation models must be quickly and easily created for use in clinical routine. Building new or adapting existing spine multibody simulation (MBS) models is time-consuming due to their complex structure. To overcome this limitation, we developed a simple, efficient method by which to automatically adjust the lumbar curvature orientation of the spine model. The method extracts a new 3D lordosis curve from patient-specific data in the preprocessing step. Then the vertebrae and all linked spinal structures of an existing spinal simulation model are transformed so that the lumbar lordosis follows the curve obtained in the first part of the method. To validate the proposed approach, three independent experts measured the Cobb angle in the source and the generated spine alignments. We calculated a mean absolute error of 1.29° between the generated samples and the corresponded ground truth. Furthermore, the minor deviation in the root mean square error (RMSE) of 0.0012 m2 between the areas under the alignment curves in the original and target lordosis curvatures indicated the accuracy of the proposed method. The proposed method demonstrated that a new patient-specific simulation model can be generated in a short time from any suitable data source.
]]>Biomechanics doi: 10.3390/biomechanics3010014
Authors: Aki-Matti Alanen Olivia L. Bruce Lauren C. Benson Mathieu Chin Carla van den Berg Matthew J. Jordan Reed Ferber Kati Pasanen
This study aimed to examine the utility of inertial measurement unit (IMU) technology to identify angle, step-specific, and side-specific differences between youth soccer players with and without a history of lower limb injury during soccer-specific field tests. Thirty-two youths (mean age 16.4 years) who were elite soccer players (Females n = 13, Males n = 19) wore IMUs during pre- and postseason soccer-specific change-of-direction assessments. A response feature analysis was used to compare the change in peak resultant acceleration of the groups at a level of significance of p < 0.05. Statistical analysis revealed significant differences in change of peak resultant acceleration of right leg final foot contact in a 180° pivot turn (p = 0.012, ES = 1.0) and a 90° cut (p = 0.04, ES = 0.75) between the two groups. These data suggest that players with a history of lower limb injury might experience greater angle and side-specific change within a season in peak resultant acceleration when compared with injury-free athletes. This study demonstrates that IMUs may present a useful method to analyze youth soccer players’ change of direction movement after returning to play. These results can inform future studies investigating player monitoring and may prove to be a useful tool for coaches when designing individualized training programs in this population.
]]>Biomechanics doi: 10.3390/biomechanics3010013
Authors: John L. Cerillo Alexander N. Becsey Chai P. Sanghadia Kevin T. Root Brandon Lucke-Wold
Spinal bracing is a common non-surgical technique that allows clinicians to prevent and correct malformations or injuries of a patient’s spinal column. This review will explore the current standards of practice on spinal brace utilization. Specifically, it will highlight bracing usage in traumatic injuries, pregnancy, pediatrics, osteoporosis, and hyperkyphosis; address radiological findings concurrent with brace usage; and provide an overview of the braces currently available and advancements in the field. In doing so, we aim to improve clinicians’ understanding and knowledge of bracing in common spinal pathologies to promote their appropriate use and improve patient outcomes.
]]>Biomechanics doi: 10.3390/biomechanics3010012
Authors: Pourya Bazyar Andreas Baumgart Holm Altenbach Anna Usbeck
Specific finite detail modeling of the human body gives a capable primary enhancement to the prediction of damage risk through automobile impact. Currently, car crash protection countermeasure improvement is based on an aggregate of testing with installed anthropomorphic test devices (i.e., ATD or dummy) and a mixture of multibody (dummy) and finite element detail (vehicle) modeling. If an incredibly easy finite element detail version can be advanced to capture extra statistics beyond the abilities of the multi-body structures, it might allow advanced countermeasure improvement through a more targeted prediction of overall performance. Numerous research has been done on finite element analysis of broken femurs. However, there are two missing pieces of information: 1- choosing the right material properties, and 2- designing a precise model including the inner structure of the bone. In this research, most of the chosen material properties for femur bone will be discussed and evaluated.
]]>Biomechanics doi: 10.3390/biomechanics3010011
Authors: Raffaele Pertusio Silvestro Roatta
In biomedical studies as well as in clinical trials, it is often useful to have a reliable measure of the force exerted by the body (e.g., clenching force at the teeth or pinch force at fingertips) or on the body by external stimuli (e.g., taps to elicit reflexes or local pressure for nociceptive stimulation). Thin-film sensors such as FlexiForce® provide a very handy and versatile solution for these applications, but can be easily damaged and offer poor accuracy and repeatability, being heavily affected by the surface material they come into contact with. The aim of the study is the realization of a 3D-printed housing that completely embeds the sensor, thus providing mechanical protection and increasing the reliability of the measurement. The increasing availability of 3D printers and of printing materials for medical use allows the user to shape the housing according to specific needs, with short developing time and low cost.
]]>Biomechanics doi: 10.3390/biomechanics3010010
Authors: Keita Honda Yusuke Sekiguchi Shin-Ichi Izumi
Older adults have a smaller effective living space and reduced physical activity. Although walking ability in various living spaces is necessary to maintain a healthy life and a high level of physical activity, it is unclear how older adults adapt to compliant surfaces when walking. The purpose of this study was to determine the differences in the trunk and lower limb kinematics while walking on a level versus compliant surface, and the effect of aging on these kinematic changes. Twenty-two healthy individuals (aged from 20–80 years) were asked to walk along a 7-m walkway at a comfortable speed on a level and compliant surface. Gait kinematics were measured using a three-dimensional camera-based motion analysis system. We found that knee and hip flexion and ankle plantarflexion angles in the early stance phase and thoracic flexion angle throughout the gait cycle were significantly increased when walking on a compliant surface versus a level surface. The change in the thoracic flexion angle, ankle plantarflexion angle, and cadence between level and compliant surfaces was significantly correlated with age. Therefore, older adults use increased thoracic flexion and ankle plantarflexion angles along with a higher cadence to navigate compliant surfaces.
]]>Biomechanics doi: 10.3390/biomechanics3010009
Authors: Akihiro Tamura Keita Shimura Yuri Inoue
The purpose of this study was to clarify the characteristics of lower-extremity kinematics during the running of soccer players with chronic ankle instability (CAI) in comparison to those without CAI. Twenty-two male college soccer players participated in this study. Twelve players were assigned to the CAI group and ten players to the non-CAI group, and players were diagnosed according to the Cumberland Ankle Instability Tool. Kinematic data of the hip, knee, ankle, foot, and ground reaction force components during the stance phase of running were obtained using a three-dimensional motion analysis system. The results revealed that soccer players with CAI who landed with ankle inversion and other characteristic kinematics in their lower extremity during the stance phase of running were similar to those without CAI. These results show that running kinematics in soccer players are not affected by the presence or absence of CAI. Future studies based on the results of this study may contribute to the analysis of the risk of developing CAI during soccer and may also help prevent lateral ankle sprains.
]]>Biomechanics doi: 10.3390/biomechanics3010008
Authors: Ahad Behboodi Ashwini Sansare Samuel C. K. Lee
Smoothness is a hallmark of skilled, coordinated movement, however, mathematically quantifying movement smoothness is nuanced. Several smoothness metrics exist, each having its own limitations and may be specific to a particular motion such as upper limb reaching. To date, there is no consensus on which smoothness metric is the most appropriate for assessing cycling motion in children with cerebral palsy (CP). We evaluated the ability of four preexisting metrics, dimensionless jerk, spectral arc length measure, roughness index, and cross-correlation; and two new metrics, arc length and root mean square error, to quantify the smoothness of cycling in a preexisting dataset from children with CP (mean age 13.7 ± 2.6 years). First, to measure the repeatability of each measure in distinguishing between different levels of un-smoothness, we applied each metric to a set of simulated crank motion signals with a known number of aberrant revolutions using subjects’ actual crank angle data. Second, we used discriminant function analysis to statistically compare the strength of the six metrics, relative to each other, to discriminate between a smooth cycling motion obtained from a dataset of typically developed children (TD), the control group (mean age 14.9 ± 1.4 years), and a less smooth, halted cycling motion obtained from children with CP. Our results show that (1) ArcL showed the highest repeatability in accurately quantifying an unsmooth motion when the same cycling revolutions were presented in a different order, and (2) ArcL and DJ had the highest discriminatory ability to differentiate between an unsmooth and smooth cycling motion. Combining the results from the repeatability and discriminatory analysis, ArcL was the most repeatable and sensitive metric in identifying unsmooth, halted cycling motion from smooth motion. ArcL can hence be used as a metric in future studies to quantify changes in the smoothness of cycling motion pre- vs. post-interventions. Further, this metric may serve as a tool to track motor recovery not just in individuals with CP but in other patient populations with similar neurological deficits that may present with halted, unsmooth cycling motion.
]]>Biomechanics doi: 10.3390/biomechanics3010007
Authors: Carina Thomas Kevin Nolte Marcus Schmidt Thomas Jaitner
Children have different anthropometrical size ratios in relation to ball and basket compared to adults, but usually compete on the same basket height and field. Therefore, they have to adapt their throwing technique, which might result in movement patterns unfavorable for long-term performance development. In this study, we analyze how children adapt their throwing techniques to different conditions. Seven basketball players (10.14 ± 1.12 years) completed a total of 60 throws, combining different ball sizes, basket heights, and distances. The throwing movements were captured by a 3D motion capture system. Accumulated distances between all time courses of angles, angular accelerations, and velocities served as similarity measures and were analyzed by cluster analysis, including purity measures. Considering all throws, a division into seven clusters separated each individual. For all subjects, distances accounted for the most changes in the throwing motion (purity 0.81–1). In the subclusters, the basket heights were not a decisive condition (purity 0.42–0.63). However, an increase in purity was found compared to the main clusters. Children seem to adapt their movement behavior primarily to throwing distances and subordinately to basket heights, which indicates that changing playing conditions (e.g., closer 3-point line, lower baskets) might be beneficial in mini-basketball.
]]>Biomechanics doi: 10.3390/biomechanics3010006
Authors: Biomechanics Editorial Office Biomechanics Editorial Office
High-quality academic publishing is built on rigorous peer review [...]
]]>Biomechanics doi: 10.3390/biomechanics3010005
Authors: Isaura Leite Pedro Fonseca Lurdes Ávila-Carvalho João Paulo Vilas-Boas Márcio Goethel Luis Mochizuki Filipe Conceição
The biomechanical analysis of Acrobatic Gymnastics elements has not been extensively explored in scientific research to date. Due to the increased challenge of implementing experimental protocols and collecting data from multiple individuals, it is required to develop strategies that allow a safe, valid and reproducible methodology. This work aims to collect information and systematically analyze the biomechanical approach in Acrobatic Gymnastics to date. A search was conducted in the Web of Science, Scopus, EBSCO, PubMed and ISBS databases. After the selection and quality-control phases, fourteen documents were included. The results revealed that the biomechanical research in Acrobatics has been focused on balance evaluation, in which the force plate and the center of pressure are the most used instrument and variable, respectively. Research has been focused on kinetics evaluation. Kinematics analysis of pair/group elements would provide scientific answers to unresolved problems, considering that Gymnastics provides almost limitless possibilities to study human motion. Researchers should focus on the type of element, difficulty degree, main characteristics, relationship between the instrument and floor surface specificity and safety conditions. We encourage gymnastics clubs and coaches to establish networks with biomechanics laboratories, allowing to bridge the gap between research and practice.
]]>Biomechanics doi: 10.3390/biomechanics3010004
Authors: Bradley C. Jackson Catherine E. Rogerson Debbie A. Bradney Katherine M. Breedlove Thomas G. Bowman
Research in hockey has found that preparedness and activity alter head impact magnitudes. It is unknown if similar occurrences take place in soccer. Therefore, our study purpose was to determine differences in the magnitudes and frequencies of head impacts due to sex and preparedness. Sixteen female (age: 19 ± 1.05 years, height: 163.68 ± 5.03 cm, mass: 61.36 ± 4.99 kg) and 14 male (age: 20 ± 1.07 years, height: 180.34 ± 5.58 cm, mass: 74.357 ± 8.64 kg) Division III intercollegiate soccer players were included in this study. The independent variables were sex and preparedness (anticipated with good body position, anticipated with poor body position, and unanticipated). xPatch sensors (X2 Biosystems, Seattle, WA, USA) applied over the participants’ right mastoid processes for practices and games provided the frequency and biomechanics of all of the head impacts over 10 g. A total of 860 female and 870 male impacts were verified and coded by preparedness and activity during 1182 female (IR = 727.58, CI = 678.95–776.21) and 801 male (IR = 1086.14, CI = 1013.97–1158.32; IRR = 1.49, CI = 1.36–1.64) exposures. The interaction between sex and preparedness was significant for the combined dependent variables (multivariate F6,3442 = 3.67, p = 0.001, ηp2 < 0.01). Male and female intercollegiate soccer players, although exposed to different frequencies of head impacts, sustained similar magnitude impacts to the head within the preparedness categories. Training interventions should aim at improving technique while sustaining impacts as both sexes often received impacts while unprepared.
]]>Biomechanics doi: 10.3390/biomechanics3010003
Authors: Rudri Purohit Shuaijie Wang Tanvi Bhatt
We examined the effect of aging and cortical stroke on the rate of motor adaptation (adaptation rate) and amount of performance gains (adaptation plateau) in balance skills. Fourteen older (≥60 years) and fifteen younger (<60 years) adults with chronic stroke, and thirteen healthy older adults (≥60 years) participated. Participants experienced 8 consecutive gait-slips (≤45 cm) to their non-paretic/dominant limb. Slip outcome (backward/no balance loss) was compared using generalized estimating equations (GEE). Proactive (pre-slip stability) and reactive adjustments (post-slip stability, slip displacement and velocity, and compensatory step length) were compared using non-linear regression models. GEE showed the main effect of group, trial, and group × trial interaction for slip outcome (p < 0.05). There were no differences in the adaptation rate for proactive and reactive variables and plateau for proactive variables (p > 0.05). However, both stroke groups demonstrated a smaller adaptation plateau for the majority of reactive variables compared to healthy older adults (p < 0.05). The rate of adaptation to gait-slips does not slow with aging and cortical stroke; however, cortical stroke, age notwithstanding, may reduce performance gains in reactive balance skills, possibly hindering retention and transfer to real-life scenarios. People with stroke may need adjunctive therapies/supplemental agents to apply laboratory-acquired balance skills to daily life.
]]>Biomechanics doi: 10.3390/biomechanics3010002
Authors: Prem Nath Yadav Gurpreet Singh Shubham Gupta Arnab Chanda
A cerebral aneurysm is a medical condition described as the bulging out of the cerebral artery under adverse pressure conditions. Patients with such medical conditions have a mortality of 20% and additional morbidity of 30–40% due to aneurysm rupture. The currently used imaging tools such as MRI and CT scans only provide geometrical information of the aneurysm and not the rupture risk associated with the progression of the aneurysm. A novel computational modeling framework was developed to model aneurysm progression and evaluate the stress distribution under varying pressure loading conditions to bridge this gap. Image segmentation was used to segment two middle cerebral arteries (MCA) and reconstructed to design aneurysm models at vulnerable sites for aneurysm progression simulation. Five aneurysm sizes and two different wall thicknesses were modeled to simulate different stages of aneurysm progression. Three pressures (i.e., diastolic, systolic, and hypertensive) were adopted to mimic the realistic pressure loading scenario for the middle cerebral arteries, and the stress distributions across all the models were estimated to understand the rupture risk. It was observed that the induced stresses in the aneurysm walls increased with an increase in the aneurysm diameter and blood pressure. Additionally, an aneurysm with a large diameter and thin walls exhibited a high risk of rupture, especially at high blood pressures. The reported results are anticipated to help medical practitioners predict rupture risks with known imaging-based aneurysm sizes and make timely decisions for such aneurysm conditions.
]]>Biomechanics doi: 10.3390/biomechanics3010001
Authors: Nolwenn Fougeron Isabelle Rivals Nathanaël Connesson Grégory Chagnon Thierry Alonso Laurent Pasquinet Stéphane Auguste Antoine Perrier Yohan Payan
Recently, a new bi-layer dressing was proposed by Urgo RID to reduce the healing time of pressure ulcers (PU). This dressing was numerically evaluated in previously published work. In the current work, the influence on the maximal shear strains of modelling parameters such as the dressing local geometry, the pressure applied by the gauze inside the wound, the wound deepness, and the mattress stiffness, was assessed. A sensitivity analysis was performed on these four parameters. Among all experiments, the mean maximal Green–Lagrange shear strain was 0.29. The gauze pressure explained 60% of the model response in terms of the volume of tissues under strains of 0.3, while the wound deepness explained 28%. The mattress had a significant, but low impact, whereas the dressing local geometry had no significant impact. As expected, the wound deepness was one of the most influential parameters. The gauze turned out to be more significant than expected. This may be explained by the large range of values chosen for this study. The results should be extended to more subjects, but still suggest that the gauze is a parameter that might not be neglected. Care should also be taken in clinical practice when using gauze that could have either a positive or negative impact on the soft tissues’ strains. This may also depend on the wound deepness.
]]>Biomechanics doi: 10.3390/biomechanics2040048
Authors: Antonio C. F. Andrade Danilo S. Catelli Bruno L. S. Bedo Guilherme M. Cesar Thiago F. Santos Eduardo B. Junqueira Paulo R. P. Santiago
Different measurements of foot morphological characteristics can effectively predict foot muscle strength. However, it is still uncertain if structural and postural alterations leading to foot pronation could be compensated with more efficient function of the intrinsic foot muscles and how mobility and strength are associated. Additionally, the relationship between foot mobility and the strength of the intrinsic muscles that control the foot arch is still unclear. Therefore, this study aimed to investigate the morphological parameters between dominant and non-dominant feet and the relationship between the intrinsic foot muscle strength and foot mobility in recreational runners. We used a cross-sectional study design to evaluate twenty-four healthy recreational runners (minimum 15 km/week) with an average training history of 70 ± 60 months. Foot Posture Index (FPI-6), isometric intrinsic muscle strength, overall morphology, and normalized mobility of both feet were assessed. Parametric tests analyzed the unidimensional measures, and paired analysis determined differences between dominant and non-dominant sides. Pearson’s and Spearman’s correlation coefficients determined the relationships between normalized strength and the variables of interest (CI = 95%). There was no significant association between intrinsic foot muscle strength and mobility. The only difference observed was between the dominant and non-dominant foot regarding the normalized foot length and midfoot width during non-weight-bearing, with small and medium effect sizes, respectively. Neither foot morphology nor foot mobility was associated with strength from intrinsic foot muscles in healthy recreational runners. Further work should explore the relationship investigated in our study with professional athletes and runners with symptomatic lower limb injuries to potentialize training and rehabilitation protocols.
]]>Biomechanics doi: 10.3390/biomechanics2040047
Authors: Haruki Yaguchi Yusuke Sekiguchi Keita Honda Kenichiro Fukushi Chenhui Huang Kentaro Nakahara Cheng Zhenzhao Shin-Ichi Izumi
Background: Stair climbing is a part of the basic activities of daily living. Previous biomechanical analyses of stairs have been conducted in the laboratory, resulting in only a few steps. Therefore, the biomechanical characteristics of long stair climbing in the real world remain unclear. The purpose of this study was to identify differences in kinematic and kinetic in the lower limb between the beginning and end phases of long stair climbing in an outdoor environment using a wearable motion analysis system. Eight subjects (four males and four females) were included in the data analysis (age: 23.6 ± 0.5 years). The long stair was 66 consecutive steps out of 202 stone steps. A wearable motion analysis system comprised six inertial measurement units and foot pressure sensors. The maximum ankle joint flexion angle in the end phase was significantly increased more than in the beginning phase (p < 0.001). On the other hand, the other kinematic, kinetic, and stair climbing speeds showed no significant difference between the phases. The findings indicated that fatigue during long stair climbing might increase ankle dorsiflexion to compensate for forwarding propulsion.
]]>Biomechanics doi: 10.3390/biomechanics2040046
Authors: Nickolai J. P. Martonick Craig P. McGowan Russell T. Baker Lindsay W. Larkins Jeff G. Seegmiller Joshua P. Bailey
The single leg squat (SLS), forward step down (FSD), and lateral step down (LSD) are clinically reliable movement screens for identifying motion imbalances. The current understanding for the kinematic profiles of each task is limited to discrete time points such as peak knee flexion. However, analyses of the entire movement would better aid clinicians when selecting the appropriate task for rehabilitation or movement screen purposes. The current study used Statistical Parametric Mapping to ascertain differences in the kinematic waveforms for the entire duration of each task. The trunk, pelvis, hip, and knee were analyzed in the sagittal and frontal planes. Data for each variable and task were analyzed from 0–100% of the movement. Primary findings indicated that the FSD provoked a greater magnitude of knee abduction than the SLS and LSD from 26–66% of the movement. The SLS generated the greatest amounts of trunk, pelvic, and hip flexion for the entirety of the movement. The LSD elicited the least amount of ipsilateral trunk lean (90–100%). Thus, the FSD may be optimal for assessing frontal plane knee motion as a screen for injury risk, while the SLS has potential to place increased sagittal plane demand on the muscles of the hip.
]]>Biomechanics doi: 10.3390/biomechanics2040045
Authors: Kristin M. Bowers Lori D. Terrones Elizabeth G. Croy Pierre-Yves Mulon Henry S. Adair David E. Anderson
The purpose of this study was to analyze the effects of locking plate fixation used for bridging of tibial segmental ostectomy and of cast immobilization on gait biomechanics in goats. We hypothesized that stable fixation of a segmental bone defect, using a locking plate construct, would result in minimal changes in biomechanical variables of gait in goats, but full-limb immobilization would result in lasting alterations in the immobilized limb’s gait kinetics. A pressure-sensing walkway was used to measure biomechanical characteristics for stride, gait, and walking vertical force. Thirteen, non-lame adult Boer-cross goats were trained to walk over a pressure-sensing walkway prior to instrumentation. Segmental ostectomy was performed on the right hind tibia of each goat and the defect was stabilized using bridging plate fixation with a locking compression plate. Per the protocol of an ongoing orthopedic study, the same goats underwent right hindlimb cast immobilization between one and four months postoperatively. Data was collected preoperatively and then over twelve months postoperatively in goats with unrestricted mobility. Statistical analysis revealed no significant alterations in hindlimb kinematics or maximum force when comparing the period after surgery with that after cast immobilization; significant decreases in forelimb stride length and velocity were noted postoperatively but normalized prior to cast placement, suggesting the overall functional stability of fixation. Cast immobilization had a profound and sustained effect on gait with significant alterations in both forelimb kinetics and hindlimb kinetics and kinematics for the remainder of the trial period; increased hindlimb asymmetry characterized by greater weight distribution and impulse to the left hindlimb was observed, suggesting the potential for long-term and/or permanent detrimental effects of prolonged limb immobilization.
]]>Biomechanics doi: 10.3390/biomechanics2040044
Authors: Xiaohan Xu Guojiong Hu Genevieve K. R. Williams Fenghao Ma
(1) Background: We aimed to compare gender differences in knee biomechanics and neuromuscular characteristics, and to determine the relationships between lower limb muscle pre-activations and knee biomechanics during a single leg drop landing, in order to identify riskier landing patterns to prevent injury and intervene properly. (2) Methods: Descriptive laboratory cross-sectional study on 38 healthy untrained subjects with low to moderate physical activity status. (3) Results: During the initial-contact phase of landing, females demonstrated greater peak vertical ground reaction force (GRF) normalized to body weight (49.12 ± 7.53 vs. 39.88 ± 5.69 N/kg; p < 0.001; Hedge’s g = 1.37), peak knee anterior reaction force normalized to body weight (0.23 ± 0.04 vs. 0.17 ± 0.05 N/kg; p < 0.001; Hedge’s g = 1.33), and decreased pre-activation of the semitendinosus (45.10 ± 20.05% vs. 34.03 ± 12.05%; p = 0.04; Hedge’s g = 0.67). The final regression equation was peak knee anterior reaction force = 0.024 + 0.025 (peak knee flexion moment) − 0.02 (semitendinosus-to-vastus lateralis pre-activation ratio) + 0.003 (peak vertical GRF) (R2 = 0.576, p < 0.001). (4) Conclusions: Overall, the data provided in this study support that a reduced semitendinosus-to-vastus lateralis pre-activation ratio predicted an increase in knee anterior reaction force and potentially an increase in ACL forces. Female non-athletes had gender-specific landing characteristics that may contribute to ACL injury. Future studies are warranted to consider more possible predictors of non-contact ACL injury.
]]>Biomechanics doi: 10.3390/biomechanics2040043
Authors: Abdullah Al Masud Chwan-Li Shen Ming-Chien Chyu
The application of Whole Body Vibration (WBV) has been demonstrated to be effective in improving muscle strength/power by a number of studies, but an optimal training protocol has never been established. This paper presents a review of studies on the effects of WBV on muscles and an analysis of data to identify the optimal protocols for the most beneficial neuromuscular responses in terms of vibration frequency, amplitude, knee flexion angle, body posture (standing, sitting, supine, prone), muscle type (quadriceps, hamstrings), and vibration mode (superoinferior, anteroposterior, rotational). Ninety articles were selected for final review from initially selected 2093 articles using PRISMA guidelines. The findings suggest that the beneficial effects of WBV increase with frequency and amplitude but the optimal frequency and amplitude have not been established. The effect of the knee flexion angle is not clear. The optimal WBV protocol should be determined by considering the adverse effects of WBV on all parts of the human body including that related to head acceleration. WBV in sitting or lying positions may provide a better muscle response than standing. Directions for future research are discussed with regard to establishing the optimal WBV protocol as a safe and effective therapeutic/exercise modality for improving muscle strength and health.
]]>Biomechanics doi: 10.3390/biomechanics2040042
Authors: Damjana V. Cabarkapa Dimitrije Cabarkapa Andrew C. Fry Shay M. Whiting Gabriel G. Downey
While being an integral part of both the offensive and defensive segments of the game, the biomechanical parameters of setting motions remain understudied in the scientific literature. Thus, the purpose of the present study was to examine differences in kinetic and kinematic characteristics between: (a) three types of setting motions (i.e., front, middle, back); (b) two types of setting approaches (i.e., stationary, step-in); and (c) proficient (PRO) and non-proficient (N-PRO) volleyball players. Twenty recreationally active females performed five stationary and five step-in setting approaches to Zone 4–2 in a randomized order. Uni-dimensional force plate sampling at 1000 Hz and high-definition camera recording at 30 fps were used to obtain kinetic and kinematic variables of interest. The total number of setting attempts performed by each subject was 30, accounting for a grand total of 600 attempts. PRO setters had less knee flexion, shoulder flexion, and ankle dorsiflexion at the initial concentric phase of the volleyball setting motion when compared to the N-PRO setters. Moreover, significantly greater peak concentric and landing forces, impulse, rate of force development, and vertical jump height were observed for PRO setters compared to N-PRO setters, while no significant differences were found between different setting targets and approaches.
]]>Biomechanics doi: 10.3390/biomechanics2040041
Authors: Rajat Singh Jordan Fleury Sonu Gupta Nate Bachman Brent Alumbaugh Gannon White
The study presents a novel scheme that recognizes and classifies different sub-phases within the involuntary breathing movement (IBM) phase during breath-holding (BH). We collected force data from eight recreational divers until the conventional breakpoint (CB). They were in supine positions on force plates. We segmented their data into no-movement (NM) phases, i.e., the easy phase (EP) and IBM phase (comprising several events or sub-phases of IBM). Acceleration and jerk were estimated from the data to quantify the IBMs, and phase portraits were developed to select and extract specific features. K means clustering was performed on these features to recognize different sub-phases within the IBM phase. We found five–six optimal clusters separating different sub-phases within the IBM phase. These clusters separating different sub-phases have physiological relevance to internal struggles and were labeled as classes for classification using support vector machine (SVM), naive Bayes (NB), decision tree (DT), and K-nearest neighbor (K-NN). In comparison with no feature selection and extraction, we found that our phase portrait method of feature selection and extraction had low computational costs and high robustness of 96–99% accuracy.
]]>Biomechanics doi: 10.3390/biomechanics2040040
Authors: Michele Aquino John Petrizzo Robert M. Otto John Wygand
Landing kinetics and kinematics have historically been correlated with potential injury. A factor that requires more attention associated with its correlation to injury risk includes the impact of physiological fatigue. Fatigue is a multifaceted phenomenon involving central and peripheral factors resulting in a slowing or cessation of motor unit firing and a decrease in maximal force and power. Sports participation rarely results in momentary muscular failure occurring, as many sports consist of intermittent periods of activity that are interspersed with short rest periods that allow for recovery to take place. However, over the course of the competition, fatigue can still accumulate and can result in impaired performance. Current literature on the topic struggles to replicate the peripheral and central metabolic stresses required to induce a state of fatigue that would be equivalent to athletic exposure. Furthermore, the current literature fails to demonstrate consistency regarding the kinetic implications associated with fatigue, which may be secondary to the inconsistencies associated with fatigue protocols utilized. This article focuses on providing an overview of the current literature associated with fatigue’s impact on the kinetics associated with landing from a jump. The article will provide a prospective methodology utilizing repeat bouts of the Wingate Anaerobic Power Test. The proposed protocol may help further our understanding of the relationship between fatigue and lower extremity biomechanics.
]]>Biomechanics doi: 10.3390/biomechanics2040039
Authors: Michael Goutnik Joel Goeckeritz Zackary Sabetta Tala Curry Matthew Willman Jonathan Willman Theresa Currier Thomas Brandon Lucke-Wold
Neurotrauma continues to contribute to significant mortality and disability. The need for better protective equipment is apparent. This review focuses on improved helmet design and the necessity for continued research. We start by highlighting current innovations in helmet design for sport and subsequent utilization in the lay community for construction. The current standards by sport and organization are summarized. We then address current standards within the military environment. The pathophysiology is discussed with emphasis on how helmets provide protection. As innovative designs emerge, protection against secondary injury becomes apparent. Much research is needed, but this focused paper is intended to serve as a catalyst for improvement in helmet design and implementation to provide more efficient and reliable neuroprotection across broad arenas.
]]>Biomechanics doi: 10.3390/biomechanics2040038
Authors: Kota Z. Takahashi Rebecca L. Krupenevich Amy L. Lenz Luke A. Kelly Michael J. Rainbow Jason R. Franz
Much of our current understanding of age-related declines in mobility has been aided by decades of investigations on the role of muscle–tendon units spanning major lower extremity joints (e.g., hip, knee and ankle) for powering locomotion. Yet, mechanical contributions from foot structures are often neglected. This is despite the emerging evidence of their critical importance in youthful locomotion. With the rapid growth in the field of human foot biomechanics over the last decade, our theoretical knowledge of young asymptomatic feet has transformed, from long-held views of the foot as a stiff lever and a shock absorber to that of a versatile system that can modulate mechanical power and energy output to accommodate various locomotor task demands. In this perspective review, we predict that the next set of impactful discoveries related to locomotion in older adults will emerge by integrating the novel tools and approaches that are currently transforming the field of human foot biomechanics. By illuminating the functions of the feet in older adults, we envision that future investigations will refine our mechanistic understanding of mobility deficits affecting our aging population, which may ultimately inspire targeted interventions to rejuvenate the mechanics and energetics of locomotion.
]]>Biomechanics doi: 10.3390/biomechanics2030037
Authors: Apostolina Foskolou Analina Emmanouil Konstantinos Boudolos Elissavet Rousanoglou
In popular fitness modalities, the participants often perform abdominal breathing while maintaining stable or rather unstable as well as inverted body stances that may challenge the respiratory muscles’ activation. This study aimed to examine the abdominal breathing effect on postural stability and the respiratory muscles’ activation during four body stances: the Upright Stance, the Quadrupled Inverted V, the Elbow Side-Bridge, and the Headstand. Participants (n = 29) maintained (40 s) the body stances under regular and abdominal breathing (the latter verified through visual inspection and 3D inertial sensing of the abdominal wall angular displacements, LORD-MicroStrain®, 100 Hz, MicroStrain, Inc., Williston, VT, USA). The trajectory of the center of pressure (CoP) (Kistler force plate, 100 Hz, Kistler Group, Winterthur, Switzerland) was recorded in synchronization with the respiratory muscles’ (sternocleidomastoid, external intercostals, diaphragm, rectus abdominis) vibromyographic activation (Biopac VMG sensors, 2000 Hz, Biopac Systems, Inc., Santa Barbara, CA, USA). Abdominal breathing had a significant (p ≤ 0.05) deteriorating effect on postural stability and an increasing one on the respiratory muscles’ activation; however, this was not consistent across body stances. The body stance specificity of the abdominal breathing effect justifies the purpose of the present study. Thus, before the request for abdominal breathing in popular fitness modalities, one should acknowledge the postural and the breathing demands of each particular stance, particularly for the inverted ones.
]]>Biomechanics doi: 10.3390/biomechanics2030036
Authors: Yusuke Sekiguchi Dai Owaki Keita Honda Shin-Ichi Izumi
The coordination of joint moments in the same limb—otherwise known as kinetic interjoint coordination—during gait in patients with hemiparesis remains unclear. This study clarifies the characteristics of kinetic interjoint coordination in the lower limbs using a principal component analysis (PCA). Using a three-dimensional motion analysis system and force plates, the kinematic and kinetic data from 29 patients with hemiparesis and 12 healthy controls were measured when they walked along a 7 m walkway. The spatiotemporal principal components (PCs) of the hip, knee, and ankle joint moments were calculated using a PCA and the motor modules during gait were identified. We adopted a case–control study design to clarify the kinetic interjoint coordination characteristics during gait in patients with hemiplegia. As the results of comparisons between the patients and controls showed, the peak timing of the first PC, which had high loadings of hip and ankle joint moments on the paretic side, was significantly earlier than that on the other sides. The loading of the knee joint moment for the first PC on the paretic side was significantly lower than that on the non-paretic side (p < 0.05), which was highly variable with negative and positive values. The results demonstrated that the first motor module comprising hip and ankle joint moments on the paretic side during gait in patients with hemiparesis may be merged with knee joint flexion or the extension moment, and may have an atypical temporal component. The index of kinetic interjoint coordination would be a useful tool for robotic-based systems for effective rehabilitation, which would significantly contribute to the acceleration of collaborative research in the fields of engineering and rehabilitation medicine.
]]>Biomechanics doi: 10.3390/biomechanics2030035
Authors: Shuaijie Wang Tanvi Bhatt
Stroke survivors are at a relatively higher risk of falling than their healthy counterparts. To identify the key gait characteristics affecting fall risk in this population, this study analyzed the gait kinematics and gait asymmetries for 36 community-dwelling people with chronic stroke (PwCS). According to their fall history in the last 12 months, they were divided into a fall group (n = 21) and non-fall group (n = 15), and then the gait kinematics (step length, stride length, stance time, swing time, trunk angle, and segment angles for lower limbs) and their asymmetries (symmetry ratio and symmetry index) were compared between these two groups. To investigate the relationship between fall types and gait characteristics, these variables were also compared between 11 slip-fallers and non-fallers, as well as between 7 trip-fallers and non-fallers. Our results indicated that the fallers showed smaller trunk and thigh angle, larger shank angle, and higher gait asymmetries (trunk and foot). Such changes in gait pattern could also be found in the trip-fallers, except the trunk angle. Additionally, the trip-fallers also showed a shorter step length, shorter stride length, shorter swing time, larger foot angle on the paretic side, and higher asymmetries in shank angle and step length, while the slip-fallers only showed changes in trunk angle and thigh angle and higher asymmetries in step length and foot angle compared to the non-fall group. Our results indicated that improper or pathological gait patterns (i.e., smaller thigh angle or higher foot asymmetry) increases the risk of falling in PwCS, and different fall types are associated with different gait characteristics. Our findings would be helpful for the development of fall risk assessment methods that are based on kinematic gait measurements. Implementation of objective fall risk assessments in PwCS has the potential to reduce fall-related injuries, leading to a reduction in associated hospital costs.
]]>Biomechanics doi: 10.3390/biomechanics2030034
Authors: Li Jin Michael E. Hahn
The lower–extremity system acts like a spring in the running stance phase. Vertical stiffness (Kvert) and leg stiffness (Kleg) reflect the whole–body center of mass (COM) and leg–spring system loading and response in running, while joint stiffness (Kjoint) represents joint–level dynamic loading and response. This study aimed to investigate whether Kjoint is associated with Kvert and Kleg across different running speeds. Twenty healthy subjects were recruited into a treadmill running study (1.8 to 3.8 m/s, with 0.4 m/s intervals). We found that Kjoint accounted for 38.4% of the variance in Kvert (p = 0.046) and 42.4% of the variance in Kleg (p = 0.028) at 1.8 m/s; Kjoint also accounted for 49.8% of the variance in Kvert (p = 0.014) and 79.3% of the variance in Kleg (p < 0.0001) at 2.2 m/s. Kknee had the strongest unique association with Kvert and Kleg at 1.8 and 2.2 m/s. Kjoint was associated with Kleg at a wider range of speeds. These findings built a connection between joint stiffness and limb stiffness within a certain range of running speeds. Kknee may need to be considered as an important factor in future limb stiffness optimization and general running performance enhancement.
]]>Biomechanics doi: 10.3390/biomechanics2030033
Authors: Heather R. Vanderhoof Emily A. Chavez Jeffrey D. Eggleston
Walking workstations may counteract sedentarism in working adults; however, performing dual-task walking may affect gait or work performance. The purpose of this study was to examine gait symmetry parameters and work performance while completing a fine motor dexterity task during walking workstation use. Gait function, quantified as gait symmetry, was used to identify attentional resource allocation of the co-occurring tasks during the dual-task conditions. Eighteen college-aged students performed the Purdue Pegboard Test (PPT) with left and right hands separately while using a walking workstation at a self-selected speed. Gait symmetry indices were computed on stride length and lower extremity angular joint positions and were analyzed for a comparison of the baseline and PPT dual-task conditions. No asymmetries were found in stride length or lower extremity angular joint positions at any sub-phase of gait during walking workstation use. PPT scores decreased significantly in the walking condition compared to the seated and standing conditions. Overall, gait symmetry did not change at any lower extremity angular joint position at any sub-phase; however, there was a decrease in PPT performance, which may relate to decreased work performance. However, increased exposure to the PPT task while using a walking workstation may improve work performance over time.
]]>Biomechanics doi: 10.3390/biomechanics2030032
Authors: Kade D. Wagers Nicholas J. Lobb AuraLea C. Fain Kayla D. Seymore Tyler N. Brown
Background: This study determined whether the knee and ankle muscle extensor forces increase when running with a body-borne load and whether these forces differ between the sexes. Methods: Thirty-six (twenty male and sixteen female) adults had the knee and ankle extensor force quantified when running 4.0 m/s with four body-borne loads (20, 25, 30, and 35 kg). Peak normalized (BW) and unnormalized (N) extensor muscle force, relative effort, and joint angle and angular velocity at peak muscle force for both the ankle and the knee were submitted to a mixed model ANOVA. Results: Significant load by sex interactions for knee unnormalized extensor force (p = 0.025) and relative effort (p = 0.040) were observed, as males exhibited greater knee muscle force and effort than females and increased their muscle force and effort with additional load. Males also exhibited greater ankle normalized and unnormalized extensor force (p = 0.004, p < 0.001) and knee unnormalized force than females (p = 0.005). The load increased the normalized ankle and knee muscle force (p < 0.001, p = 0.030) and relative effort (p < 0.001, p = 0.044) and the unnormalized knee muscle force (p = 0.009). Conclusion: Running with a load requires greater knee and ankle extensor force, but males exhibited greater increases in muscle force, particularly at the knee, than females.
]]>Biomechanics doi: 10.3390/biomechanics2030031
Authors: Francesca Wade Sidney Baudendistel Amanda Stone Jaimie Roper Tiphanie Raffegeau Matthew Terza Chris Hass
Mobility disability is prevalent in aging populations. While existing walking interventions improve aspects related to mobility, meaningful and sustained changes leading to preventing and reversing mobility disability have remained elusive. Split-belt treadmills can be used to train gait adaptability and may be a potential long-term rehabilitation tool for those at risk for mobility decline. As adaptability is necessary for community walking, we investigated the feasibility of a small, randomized controlled 16-week gait adaptability training program in a cohort of 38 sedentary older adults at risk for mobility disability. Individuals were randomly assigned to one of three groups: traditional treadmill training, split-belt treadmill training, or no-contact control. Both treadmill interventions included progressive training 3 days a week, focusing on increasing duration and speed of walking. Cognitive, functional, cardiovascular, and gait assessments were completed before and after the intervention. While individuals were able to complete split-belt treadmill training, only Timed Up and Go performance was significantly improved compared to traditional treadmill training. As the stimulus provided by the split-belt training was difficult to control, we did not observe a clear benefit for split-belt treadmill training over traditional treadmill training. Our findings indicate a cautionary tale about the implementation of complex training interventions.
]]>Biomechanics doi: 10.3390/biomechanics2030030
Authors: Gonzalo Varas-Diaz Udai Jayakumar Bradford Taras Shuaijie Wang Tanvi Bhatt
This study investigated the feasibility of a perturbation-based balance protocol that incorporates a novel computer-controlled movable platform, the Surefooted Trainer, to induce losses of balance during overground walking under various environmental conditions. Twenty apparently healthy older adults (66.7 ± years old) participated in this study. The acceptability and safety of the perturbation-based balance protocol were assessed by tracking adherence, adverse events, and subjective physical and mental demands after the intervention. Additionally, biomechanical variables during perturbed and non-perturbed trials were analyzed and compared with behavioral outcomes. Overall, 95% of the participants completed the study. There were no serious or non-serious adverse events. The margin of stability and step length after perturbations were significantly lower during slip-perturbations in which the environmental conditions were more challenging. For trip-perturbation conditions, the maximum trunk angle was higher during the trials that resulted in losses of balance. We conclude that the Surefooted Trainer is an acceptable and valid device for an overground walking perturbation-based assessment and training protocol in older adults.
]]>Biomechanics doi: 10.3390/biomechanics2030029
Authors: Lauren C. Benson Anu M. Räisänen Sartaj S. Sidhu Carolyn A. Emery
Neuromuscular training (NMT) warm-up programs effectively prevent injuries in youth, but monitoring exercise fidelity is challenging. The purpose of this study was to compare the exercise fidelity as measured via an inertial measurement unit (IMU) with direct observations of selected exercises. Youth basketball and soccer players performed single leg jumps, squat jumps, Nordic hamstring curls, and/or single leg balance exercises as part of an NMT warm-up. An IMU was placed on the lower back of each participant and the warm-up was video recorded. A physiotherapist evaluated the volume aspect of exercise fidelity (i.e., performing the prescribed number of repetitions) using the video recordings and a checklist. Algorithms were developed to count the number of repetitions from the IMU signal. The repetitions from the algorithms were compared with the physiotherapist’s evaluation, and accuracy, precision, and recall were calculated for each exercise. A total of 91 (39 female, 52 male) athletes performed at least one of the four warm-up exercises. There was an accuracy, precision, and recall of greater than 88% for all exercises. The single leg jump algorithm classified all sets correctly. IMUs may be used to quantify exercise volume for exercises that involve both impact during landing and changes in orientation during rotations.
]]>Biomechanics doi: 10.3390/biomechanics2030028
Authors: Dimitrije Cabarkapa Andrew Fry Damjana Cabarkapa Chloe Myers Grant Jones Nicolas Philipp Daniel Yu Michael Deane
While the importance of optimal two-point and three-point jump-shooting performance for securing the desired game outcome on various levels of basketball competition has been well documented, there is a limited amount of scientific literature on what biomechanical adjustments in shooting technique comprise the success of each shooting attempt. Therefore, the purpose of the present study was to examine the difference in kinetic and kinematic characteristics during the preparatory and release phases of the shooting motion between made and missed jump shots. While standing on a force plate, twenty-nine recreationally active males with prior basketball playing experience attempted 10 two-point and 10 three-point jump shots, combining for a total of 580 attempts. Simultaneously, two high-definition cameras were used to capture kinematic characteristics of interest. Higher elbow positioning during the preparatory phase of the shooting motion, relative to the shooter’s stature, was shown to be a critical kinematic adjustment that differentiated made from missed two-point jump shots. Alongside identical observations regarding the importance of the elbow placement, keeping the torso in a more erect position during the preparatory phase of the shooting motion, having a greater release angle and vertical jump height at the timepoint of the ball release, and attaining higher maximal trajectory height were critical kinematic adjustments that differentiated made from missed three-point jump shots.
]]>Biomechanics doi: 10.3390/biomechanics2030027
Authors: Vitor Ferreira Leandro Machado Adélio Vilaça Francisco Xará-Leite Paulo Roriz
Lateral wedge insoles are recommended in order to minimize the impacts of osteoarthritis of the knee. The amount of wedging required to induce a biomechanical response with clinical significance is still controversial. This study aimed to investigate the immediate biomechanical effects of different amounts of wedging in symptomatic medial knee OA. A 3D motion capture system and five force platforms were used to acquire walking kinematic and kinetic data along a 10 m walkway. Each participant was tested for six different lateral wedge insoles (0, 2, 4, 6, 8, and 10°) in a randomized order. Thirty-eight patients with medial osteoarthritis of the knee were recruited. The application of insoles resulted in an incremental reduction of the first peak of the external knee adduction moment under all experimental conditions in comparison with the control condition (0° insole). A significant increase (p < 0.05) was observed in peak ankle eversion and in ankle eversion at the first peak of the external knee adduction moment with insoles higher than 8° and 6°, respectively. Slight variations to lateral wedge insoles, greater than 2°, appear to induce significant biomechanical changes in patients with knee osteoarthritis.
]]>Biomechanics doi: 10.3390/biomechanics2030026
Authors: Massimiliano Pau Bruno Leban Micaela Porta Jessica Frau Giancarlo Coghe Eleonora Cocco
Subtle alterations of gait patterns in people with Multiple Sclerosis (pwMS) with minimal or no disability often coexist with normal spatio-temporal parameters. Here, we retrospectively investigate the existence of possible anomalies in lower limb inter-joint coordination (i.e., the functional relationship between joint pairs) in pwMS with apparently physiologic gait features. Twenty-seven pwMS with Expanded Disability Status Scale scores ≤ 2, and 27 unaffected age-and-sex-matched individuals, were tested using 3D computerized gait analysis. Raw data were processed to extract the main spatio-temporal parameters and the kinematics in the sagittal plane at the hip, knee, and ankle joints. Angle-angle diagrams (cyclograms) were obtained by coupling the flexion-extension values for the hip-knee and knee-ankle joint pairs at each point of the gait cycle. Cyclogram area, perimeter, and dimensionless ratio were employed to quantify inter-joint coordination. The results demonstrate that cyclograms of pwMS are characterized by significantly reduced perimeters for both investigated joint pairs and reduced area at the hip–knee joint pair. In the latter pair, the differences between groups involved the entire swing phase. For the knee-ankle pair, the average cyclogram of pwMS departed from normality from the late stance until the mid-swing phase. Such findings suggest that inter-joint coordination is impaired even in minimally disabled pwMS who exhibit a normal gait pattern in terms of spatio-temporal parameters. The quantitative and qualitative study of cyclogram features may provide information that is useful for better understanding the underlying mechanisms of walking dysfunctions in MS.
]]>Biomechanics doi: 10.3390/biomechanics2030025
Authors: Isabella Fessl Eric Harbour Josef Kröll Hermann Schwameder
This study aimed to investigate the effect of additional loads and sex on countermovement jump (CMJ) joint kinetics during the entire take-off impulse in males and females. Twelve female and 13 male sport students performed vertical countermovement jumps without and with additional loads up to +80% of body mass using a straight barbell. Ground reaction forces and body kinematics were collected simultaneously. A significant increase was found for peak ankle power, whereas knee and hip peak power decreased significantly as additional load increased in both males and females. Joint work increased in each joint as additional load increased, although significance was observed only in the hip joint. Peak power of each joint (22–47%) and total hip work (61%) were significantly higher for males than females. Relative joint contributions to total joint work (“joint work contribution”) remained stable as additional loads increased, whereas meaningful differences were found in the magnitudes of joint work contribution between males and females. CMJ joint kinetics and joint work contributions were distinctly influenced by additional load and sex. Hence, these differences should be considered when prescribing loaded jumps for training or testing.
]]>Biomechanics doi: 10.3390/biomechanics2020024
Authors: Jan Jens Koltermann Martin Gerber
In this scientific study, the question of the influence of the quantization error on the CoP measurement is be clarified. For this purpose, the quantization error is investigated in two scenarios, first with the technical/physical reproduction of the CoP, and then with test persons. From the results, a model is derived with which a technical and economic optimum between resolution and error can be generated for an individual case. The study was carried out with 170 healthy volunteers, aged 20–30 years. The test persons stood in a bipedal position for 15 s on a Kislter force plate (type 9260AA). In the investigation, it was shown that, for the measurement of center of pressure (CoP), signals to mostly 16-bit analog/digital converters are suitable but not, per se, the most economical variant. With the introduction of a quality criterion, a reasonable design for the planned test case can be made.
]]>Biomechanics doi: 10.3390/biomechanics2020023
Authors: Alex T. Gong Sophia L. Bidinger Aleah M. DeSchmidt Joaquin E. Batista Agnes Y. Song Alyssa L. Schul Everet Y. Wang Jack E. Norfleet Martin E. Palavecino Robert M. Sweet
A thorough biomechanical understanding of human organs is of increasing importance for designing and improving a wide range of medical technologies from simulators to medical devices. Despite the crucial need for data, little procedure-specific biomechanical testing on human tissue has been published. Specifically, pancreatic duct anastomosis, which has high rates of complications related to pancreatic duct leakage and patency, could benefit from improved assistive technologies. This study aims to help characterize the biomechanics of this critical step of the procedure by measuring the suture pullout force (SPOF) of the pancreatic duct and capsule. 216 tests were performed on 33 fresh, unfixed donated human pancreases. A previously reported uniaxial testing frame, was used to measure the SPOF of the pancreases. The mean pancreatic duct SPOF was 2.62 ± 1.11 N and the mean pancreatic capsule SPOF was 1.99 ± 1.33 N. To our knowledge, this is the first reported human pancreatic duct and capsule suture pullout measurement. These data can be used to inform a wide variety of biomedical technologies with primary interest in high-fidelity training simulators.
]]>Biomechanics doi: 10.3390/biomechanics2020022
Authors: Mathias Kolodziej Steffen Willwacher Kevin Nolte Marcus Schmidt Thomas Jaitner
Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate between injured and non-injured players. Hip sagittal plane angle at initial contact, peak ankle transverse plane angle and hip sagittal plane moment (in this hierarchical order) were indicated as risk factors for the unanticipated cutting task. Ankle, knee and hip kinematics, as well as ankle and hip kinetics, during single-leg high-risk movements can provide a good indication of injury risk in elite youth soccer players.
]]>Biomechanics doi: 10.3390/biomechanics2020021
Authors: Michihiro Yoshida Takayuki Tanaka Yoshio Tsuchiya
This paper aims to develop a regression model that explains the relationship between changes in lumbar joint stiffness and pelvic alignment (posture or shape of the bones of the pelvis and lumbar spine) due to pelvic tightening. The proposed model is based on the hypothesis that lumbar joint stiffness increases with changes in pelvic alignment. The proposed model is based on experimentally measured stiffness values and pelvic alignment data sets. The stiffness of the lumbar joint was estimated by motion analysis using a motion-capture system. Ninety-six volunteers participated in the experiment to estimate stiffness values, and the validity of using lumbar joint stiffness as the output of the model was examined. The pelvic alignment was measured through X-ray images. Pelvic alignment was measured using radiographic images, and 25 volunteers participated. The Results section states that the amount of change in the posture of the sacrum relative to the pelvis and the curvature of the lumbar spine contributes to the change in lumbar joint stiffness. Future work will include FEM analysis to validate the overall hypothesis and the validity of applying the model to a group other than those who participated in the development of the model.
]]>Biomechanics doi: 10.3390/biomechanics2020020
Authors: Eleonora Croci Marina Künzler Sean Börlin Franziska Eckers Corina Nüesch Daniel Baumgartner Andreas Müller Annegret Mündermann
Rotator cuff tears are often linked to superior translational instability, but a thorough understanding of glenohumeral motion is lacking. This study aimed to assess the reliability of fluoroscopically measured glenohumeral translation during a shoulder abduction test. Ten patients with rotator cuff tears participated in this study. Fluoroscopic images were acquired during 30° abduction and adduction in the scapular plane with and without handheld weights of 2 kg and 4 kg. Images were labelled by two raters, and inferior–superior glenohumeral translation was calculated. During abduction, glenohumeral translation (mean (standard deviation)) ranged from 3.3 (2.2) mm for 0 kg to 4.1 (1.8) mm for 4 kg, and from 2.3 (1.5) mm for 0 kg to 3.8 (2.2) mm for 4 kg for the asymptomatic and symptomatic sides, respectively. For the translation range, moderate to good interrater (intra-class correlation coefficient ICC [95% confidence interval (CI)]; abduction: 0.803 [0.691; 0.877]; adduction: 0.705 [0.551; 0.813]) and intrarater reliabilities (ICC [95% CI]; abduction: 0.817 [0.712; 0.887]; adduction: 0.688 [0.529; 0.801]) were found. Differences in the translation range between the repeated measurements were not statistically significant (mean difference, interrater: abduction, −0.1 mm, p = 0.686; adduction, −0.1 mm, p = 0.466; intrarater: abduction 0.0 mm, p = 0.888; adduction, 0.2 mm, p = 0.275). This method is suitable for measuring inferior–superior glenohumeral translation in the scapular plane.
]]>Biomechanics doi: 10.3390/biomechanics2020019
Authors: Arjan Kahlon Ashwini Sansare Ahad Behboodi
Gait analysis has applications in medical diagnosis, biometrics, and development of therapeutic rehabilitation interventions (such as orthotics, prosthetics, and exoskeletons). While offering accurate measurements, gait laboratories are expensive, not scalable, and not easily accessible. In a pandemic-afflicted world, where telemedicine is crucial, there is need for subject-driven data remote collection. This study proposed a remote and purely subject-driven procedure for reproducible and scalable collection of real-life gait data. To evaluate the feasibility of our proposed procedure, the spatiotemporal parameters of gait were compared across two real-life terrains using a smartphone application on a focus population of healthy middle-aged individuals. Previous research validated smartphone motion sensors as accurate instruments for gait analysis, but required highly supervised, controlled environments on smaller sample sizes, thereby limiting application in real-life gait analysis. To this end, a custom-designed mobile application was developed to record lower extremity angular velocities on 69 healthy middle-aged adults; factoring in a subject-driven data submission error rate (DSER) of 17.4%, there were 57 usable data sets for analysis. Comparisons of spatiotemporal gait parameters across primary outcome measures on grass versus asphalt revealed significant measurable increases in gait duration (stride time), valley depth (max swing phase), and peak-to-valley (max stance phase to max swing phase). These results demonstrated the feasibility of using smartphones for a remote and fully subject-driven gait data collection. Additionally, our data analysis showed that even in short trials, a physical environmental load has a substantial and measurable effect on the gait of the understudied middle-aged population.
]]>Biomechanics doi: 10.3390/biomechanics2020018
Authors: Lincoln Blandford Emily Cushion Ryan Mahaffey
Cognitive movement control tests are hypothesized to reveal reduced coordination variability, a feature of motor behaviour linked to clinical presentations. Exploration of this proposition via kinematic analysis of test pass and fail conditions is yet to be conducted. Kinematics (3D) were collected as 28 participants were qualitatively rated during nine trials of a cognitive movement control test. Ten female and two male participants passing the test were matched to twelve participants who failed (three males, nine females). Sagittal plane pelvis and knee angles were determined. Peak pelvic deviation and knee flexion maxima/minima were compared between groups. Classification tree analysis explored relationships between test failure and pelvis–knee intersegmental coordination strategy classifications derived from novel and traditional vector coding techniques. Coordination variability waveforms were assessed via SPM. Age, BMI, and knee flexion values did not differ between the groups (p > 0.05); however, participants rated as failing the test displayed greater pelvic deviation (p < 0.05). Classification tree analysis revealed a greater use of pelvic dominant intersegmental coordination strategies from both vector coding techniques (p < 0.001) by fail-group participants. The fail-group also displayed lower coordination variability for novel (p < 0.05), but not traditional (p > 0.05) vector coding technique waveforms, supporting the premise that the testing protocol may act as a qualitative approach to inform on features of motor behavior linked to clinical presentations.
]]>Biomechanics doi: 10.3390/biomechanics2020017
Authors: Li Jin
During locomotion, the foot–ankle system plays an important role for forward progression of the body. The center of pressure (COP) is regarded as the point of the ground reaction force (GRF) vector acting on the foot surface during the stance phase. COP movement trajectory and velocity reflect the stance phase forward progression of the foot segment and the ankle joint motion characteristics. This study aimed to investigate different levels of footwear insole stiffness on COP forward velocity, GRF and ankle joint angles during walking stance phase. Two healthy subjects (one female, one male; age 26.5 ± 6.4 years, height 168.5 ± 2.1 cm, weight 64.9 ± 5.4 kg) participated in this study. Subjects were asked to walk along a 10 m walkway at two different speeds: self–selected normal (SSN) and self–selected fast (SSF). Within each walking speed, subjects were required to walk under two different insole stiffness conditions: (1) normal shoe insole (NSI) from the testing shoe (Nike Free RN Flyknit 2017) used in this study; (2) 1.6 mm thick carbon fiber insole (CFI) fitted within the testing shoe. Stiffer insole (CFI) significantly decreased peak ankle internal rotation angle (p = 0.001) and sagittal plane angle ROM (p = 0.022); additionally, CFI significantly increased peak ankle eversion angle compared to the NSI condition (p = 0.028). In conclusion, increasing footwear insole stiffness would alter stance phase ankle joint motion at SSF walking speed. Additionally, stiffer insoles may tend to decrease COP peak velocity at the initial heel strike and the terminal stance phase. Future research should investigate the combined effects of various insole properties on lower extremity system kinematic and kinetic patterns in various locomotion activities.
]]>Biomechanics doi: 10.3390/biomechanics2020016
Authors: Rodrigo Valente André Mourato Moisés Brito José Xavier António Tomás Stéphane Avril
Ascending Thoracic Aortic Aneurysm (ATAA) is a permanent dilatation of the aorta which is usually related to tissue degeneration, hemodynamic conditions, lifestyle, environmental and genetic factors. As the mechanical conditions can become critical in a dilated aorta, a patient-specific computational model can be very useful to assist clinical decisions in the management of ATAAs. In this article, we model the biomechanical conditions of ATAA by performing Fluid–Structure Interaction (FSI) simulations in the SimVascular open-source software package. The patient-specific geometric model is reconstructed from Computed Tomography scan (CT). The numerical implementation takes into account patient-specific outlet conditions and a temporal flow variation at the model inlet. We performed a mesh convergence analysis on a new mesh reconstruction method in SimVascular and showed that it can significantly reduce the computational cost without impacting the accuracy.
]]>Biomechanics doi: 10.3390/biomechanics2020015
Authors: Rébecca Bonnaire Woo Suck Han Reynald Convert Paul Calmels Jérôme Molimard
Low back pain represents a major economic and societal challenge due to its high prevalence. Lumbar orthoses are one of the recommended treatments. Even if previous results showed their clinical effects, the detailed mode of action is still poorly known, making the device design difficult. A renewed instrumentation and experimental protocol should bring better insight into the lumbar brace–trunk mechanical interaction. This instrumentation should give detailed information on the basic physical or geometrical parameters: the pressure applied on the trunk, the body shape and the strain in the belt. The principal objective of this study was to propose and validate a new measurement protocol, based on pressure mapping systems and full-field shape and strain measurement. The feasibility of the protocol was tested along with its validity and repeatability. The influence of various parameters, which could cause changes in the measurements, was tested with six different belt configurations on one subject. Measurements were also performed to study the impact of posture on pressure and strain. Both pressure and strain appeared to be asymmetric from left to right. The pressure applied by the lumbar belt on the back varies with breathing and with posture. This study showed that full-field measurements were necessary to render the high variability of pressure or strain around the trunk, under recommendations of their use to guarantee a satisfying repeatability.
]]>Biomechanics doi: 10.3390/biomechanics2020014
Authors: Neda Alam David Newport
Patients with end stage renal disease require some form of vascular access for treatment, with Arterio-Venous Fistulas (avf) being the preferred form available due to better patency rates. However, they continue to present complications after creation, leading to early or late failure. While many studies are examining the flow in patient-specific fistulas, they often neglect the influence of vessel compliance on its hemodynamics. The objective of this study is to investigate the effect of wall compliance on the complex hemodynamics of a patient-specific brachio-cephalic avf and how it differs from a rigid fistula. Particle Image Velocimetry (piv) was used to capture the flow pattern within the fistula for both steady (Re = 1817) and pulsatile (Reav=1817, Remax=2232) flow conditions. The results were compared to rigid model measurements performed under the same Reynolds number. The streamline plots and coefficient of variation results did not differ significantly between the models; however, the non-dimensional velocity and directional variability results did vary between the two fistulas. A difference of approximately 8% was seen between the two models for both steady and pulsatile flow. The findings of this study suggest that to determine the bulk flow, a rigid model is adequate, but to capture the finer details of the flow, a compliant model is necessary.
]]>Biomechanics doi: 10.3390/biomechanics2020013
Authors: Aroj Bhattarai Andreas Johannes Horbach Manfred Staat Wojciech Kowalczyk Thanh Ngoc Tran
The objective of this paper is to present our findings on the biomechanical aspects of the virgin passive anisotropic hyperelasticity of the porcine colon based on equibiaxial tensile experiments. Firstly, the characterization of the intestine tissues is discussed for a nearly incompressible hyperelastic fiber-reinforced Holzapfel–Gasser–Ogden constitutive model in virgin passive loading conditions. The stability of the evaluated material parameters is checked for the polyconvexity of the adopted strain energy function using positive eigenvalue constraints of the Hessian matrix with MATLAB. The constitutive material description of the intestine with two collagen fibers in the submucosal and muscular layer each has been implemented in the FORTRAN platform of the commercial finite element software LS-DYNA, and two equibiaxial tensile simulations are presented to validate the results with the optical strain images obtained from the experiments. Furthermore, this paper also reviews the existing models of the active smooth muscle cells, but these models have not been computationally studied here. The review part shows that the constitutive models originally developed for the active contraction of skeletal muscle based on Hill’s three-element model, Murphy’s four-state cross-bridge chemical kinetic model and Huxley’s sliding-filament hypothesis, which are mainly used for arteries, are appropriate for numerical contraction numerical analysis of the large intestine.
]]>Biomechanics doi: 10.3390/biomechanics2010012
Authors: Lukas Steiner Alexander Synek Dieter H. Pahr
Finite element (FE) analysis can predict proximal human femoral strength. Automated meshing and identifying subregions with high relevance for strength prediction could reduce the laborious modeling process. Mesh morphing based on free-form registration provides a high level of automation and inherently creates isotopological meshes. The goals of this study were to investigate if FE models based on free-form transformed meshes predict experimental femoral strength as well as manually created FE models and to identify regions and parameters with highest correlation to femoral strength. Subject-specific meshes and FE models were created from a set of quantitative CT images (QCT) using a B-Spline registration-based algorithm. Correlation of FE-predicted bone strength and local parameters with experimental bone strength were investigated. FE models based on transformed meshes closely resembled manually created counterparts, with equally strong correlations with experimental bone strength (R2=0.81 vs. R2=0.80). The regional analysis showed strong correlations (0.6<R2<0.7) of experimental strength with local parameters. No subregion or parameter lead to stronger correlation than FE predicted bone strength. B-spline-transformed meshes can be used to create FE models, able to predict femoral bone strength and simplify FE model generation. They can be used to reveal relations of local parameters with failure load.
]]>Biomechanics doi: 10.3390/biomechanics2010011
Authors: Ivanna Kramer Sabine Bauer
Finite element (FE) modeling is a commonly used method to investigate the influence of medical devices, such as implants and screws, on the biomechanical behavior of the spine. Another simulation method is multibody simulation (MBS), where the model is composed of several non-deformable bodies. MBS solvers generally require a very short computing time for dynamic tasks, compared with an FE analysis. Considering this computational advantage, in this study, we examine whether parameters for which values are not known a priori can be determined with sufficient accuracy using an MBS model. Therefore, we propose a many-at-a-time sensitivity analysis method that allows us to approximate these a priori unknown parameters without requiring long simulation times. This method enables a high degree of MBS model optimization to be achieved in an iterative process. The sensitivity analysis method was applied to a simplified screw–vertebra model, consisting of an anterior anchor implant screw and vertebral body of C4. An experiment described in the literature was used as the basis for developing and assessing the potential of the method for sensitivity analyses and for validating the model’s action. The optimal model parameters for the MBS model were determined to be c = 823,224 N/m for stiffness and d = 488 Ns/m for damping. The presented method of parameter identification can be used in studies including more complex MBS spine models or to set initial parameter values that are not available as initial values for FE models.
]]>Biomechanics doi: 10.3390/biomechanics2010010
Authors: John G. Buckley Andrew J. Scally Chanchal Bhattacharjee
When lying supine, due to the reaction force from the mattress acting mostly through the heel, an external knee-extension joint-torque is induced that keeps the knee fully extended. This torque becomes zero if the feet are hung over the end of the support. This study investigated, in patients with knee-osteoarthritis (knee-OA) who routinely sleep supine, whether a change to such a sleeping position would ameliorate the knee pain and associated physical problems they suffer. Patients were recruited (General-Practitioners Centre, UK) over a 9-month period; those eligible (51/70) were randomly allocated to an intervention (65% female; age 71.5 [11.3] yrs; BMI, 29.20 [5.54] kg/m2; knee-OA severity, 20 mild–mod/3 severe) or control group (63% female; age, 68.3 [9.7] yrs; BMI, 28.69 [5.51] kg/m2; knee-OA severity, 17 mild–mod/2 severe). The primary outcome was improvements (0 [worst] to 100 [best]) in knee pain at 3 months and was rated in the Knee-Injury-and-Osteoarthritis-Outcome-Score questionnaire (KOOS). Secondary outcomes were improvements (0–100) in the other four KOOS-subscales. There were no differences between groups in KOOS outcomes at baseline, and there were no changes in KOOS outcomes in the control group at 3 months. Relative to the baseline KOOS values in Knee-Pain (50.1), Symptoms (52.5), Activities-of-Daily-Living (53.8) and Quality-of-Life (31.5), were all seen to improve at 3 months in the intervention group (by between 11.9 and 12.9); however, when comparing to controls, only the improvements in the subscale Activities-of-Daily-Living (which improved by 12.2) were statistically significant. Findings indicate that for those with knee-OA who routinely sleep supine, sleeping with the feet over the end of the mattress (to prevent the knee being pushed into/held in full extension) can help ameliorate the physical problems they suffer.
]]>Biomechanics doi: 10.3390/biomechanics2010009
Authors: Fanette Chassagne Jérôme Molimard Reynald Convert Clothilde Helouin-Desenne Pierre Badel Pascal Giraux
Interface pressure applied by compression bandages is the therapeutic action of the treatment of some venous or lymphatic pathologies. The so-called Static Stiffness Index, which quantifies the pressure increase from supine to standing position, is usually used to differentiate compression bandages. It was hypothesized that this pressure increase was the consequence of a change in leg geometry (blood and muscle falling down) and a change in calf soft tissue mechanical properties (muscles contraction). Calf soft tissue global stiffness of both legs of 25 patients was characterized in a sitting and standing position. This characterization was combined with interface pressure measurements applied by six different bandages. Though soft tissue mechanical properties significantly increased from sitting to standing position, no correlation was observed with the corresponding pressure increase. Thus, pressure increase is mainly attributed to a change in leg geometry.
]]>Biomechanics doi: 10.3390/biomechanics2010008
Authors: Daniel Kuhman Jutaluk Kongsuk William R. Reed Noah J. Rosenblatt Kristina Visscher Harrison Walker Christopher P. Hurt
Redistribution of mechanical output from the ankle to the hip during walking occurs with advanced age. Changes to tissues spanning the ankle may limit the joint from performing mechanical functions necessary to walk at fast speeds and older adults may redistribute work proximally to compensate. Older adults with Parkinson’s disease (PD) do not exhibit the distal-to-proximal redistribution and may therefore be limited in reaching fast walking speeds. We tested whether advanced aging, regardless of the presence of PD, limits the ability to increase motor-like behavior of the ankle as walking speed increases. We also tested whether healthy older adults—but not PD patients—would compensate for reduced motor-like behavior at the ankle with disproportionately larger mechanical redistributions at faster speeds. The 16 young, 16 older, and 8 PD-diagnosed adults walked at 0.8, 1.2, and 1.6 ms−1 on a treadmill. We used joint functional indexing to quantify motor-like behavior of the ankle and a hip-to-ankle mechanical work ratio to quantify mechanical redistribution. We found a significant group x speed interaction (p < 0.05) for motor-like behavior of the ankle, with younger adults increasing motor index more than the older and PD groups as walking speed increased. Contrary to our second hypothesis, we found a significant main effect of speed (p < 0.001) on redistribution ratios, indicating that all three groups decreased redistribution ratios as walking speed increased, but not a significant interaction.
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