Comparison of Ground Reaction Forces between Combat Boots and Sports Shoes
Round 1
Reviewer 1 Report
This paper is about the influence of different shoes on the ground reaction force. This is straight forward and the measurement tool and the study design has been used on many other studies. Here also a combat boot was included.
The introduction misses to point out the issues/injuries that should be addressed, respectively reduced by the different shoes. Here not only overuse of the joints but also blister on the skin and this type of issues needs to be mentioned.
The link between the smaller ground reaction force and the injury is missing.
An important part is not elaborated in sufficient depth. The influence of the weight of the shoes. This should be presented in more detail.
Was the stiffness respectively the hardness of the midsoles quantified?
The final part of the abstract is not entirely based on the findings, it includes speculations regarding the reason and the link towards specific injury is missing. Please revise.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Abstract
“Walking with military shoes and combat boots led to larger force transfer then running shoes potentially due to harder material used in midsole composition (i.e. styrene-butadiene rubber).” Change “then” to “than”
Introduction
Paragraph one:
Several studies indicated that external loads can contribute to an increased likelihood of injuries during operational tasks [1]. Why is only a single study cited yet it says “several studies”?
Methods
Participants
What variable was used for the power analysis to attain the needed sample size?
Data collection, paragraph 2: how many trials of each footwear condition? Ten just like the barefoot trials?
Data analyses: “Force data was” should be “Force data were”
The push-off force is a rate of unloading, not rate of force development. Unloading doesn’t contribute to forward propulsion. This is the foot coming off the ground and how quickly that occurs. Therefore, forces are not being applied to create forward propulsion, they’re being taken away from the body. The Weigerinck article that is cited in the introduction doesn’t talk about force decrements as being part of the force transferred through the metatarsals so I don’t believe that is an accurate reflection of that research. Additionally, this should be a negative number as at 90% the force number is higher than it is at 10% therefore it should be a negative value.
Figure 2: the dashed line should go from the 10% to the 90% line rather than stopping in the middle to better reflect the methodology. Additionally, if the data were normalized to barefoot forces, the vertical axis in Figure 2 shouldn’t be % body weight, the units should reflect the barefoot trials normalization.
Results
Figure 3: graph D should have the p-value attached to the 73-74% post-hoc difference.
Discussion
Paragraph 1: the connection to ankle range of motion is not made. Where is the connection between second peak force and ankle ROM?
Paragraph 3: “This could require larger force production from ankle plantar flexor muscles to develop similar joint power.” How does this relate to joint power? Gait speed was assessed in this study and the joint powers are unknown. It is more likely that the increased force production in push-off relates to the need to maintain gait speed, not joint power.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Thank you very much for the revisions. All my points have been addressed properly. Best regards
Author Response
We thank the reviewers for their input.
Reviewer 2 Report
Thank you for addressing all of the comments. Nice job.
Author Response
We thank the reviewers for their input.
