PONE-D-21-23366Effect of intrinsic foot muscle training on foot function and dynamic postural balance: a systematic review and meta-analysisPLOS ONE

Dear Dr. Wang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.The reviewers provided detailled feedback. Please address these points. 

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PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

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3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors present a systematic review study on the effectiveness of interventions that aim to improve the functioning of the Intrinsic Foot Muscles. This work has potential relevance in the prevention of foot and ankle injuries and provides a better understanding of the functional anatomy of the foot and the effects of training thereon. The manuscript overall is of sound quality, however it needs some strict improvements in the methods section in order to become eligible for publication.

MAJOR ISSUES

Aims. The aim of the current study is somewhat unclear: “Nonetheless, current studies on IFM training are cross-sectional, and evidence to support this claim is lacking. Therefore, the aim of this systematic review is to identify and determine the effect of IFM training on foot function and dynamic postural balance” (line 48-50).

This needs to be further clarified. If all past studies are cross sectional, what will be the added value of this review? In fact, later you find 13 RCTs that have been done. Why do these not feature in the introduction?

This issue is further confused at the start of the discussion where the aim seems to have been to summarize the current studies. Furthermore, judging from the methods and the results, the aim seems to have been to assess the effect of IFM training on foot biomechanical outcomes using a meta-analysis. Please clarify.

Methods. The major issues of the current manuscript lie in the methods section. Although the authors provide an adequate description of the methods to see that their approach is well thought out, there is insufficient details, and sometimes inconsistencies, that limit the reproducibility of the approach. Relating to this, the following issues will need to be addressed:

1. In the description of the search (line 57-60), it would be good to add some specification of the BOOLEAN operators used in the search.

2. In the supplementary file specifying the search, it should be specified what type of search was performed (e.g. title/abstract/keywords, topic, mesh terms) and it should be specified how the search was adapted to the different search engines.

3. There is some confusion in the use of quotation marks. In the main text, single quotation marks are used, in the supplementary file these are double marks. Please specify what was used in the searches, as these have a different meaning in the search engines.

4. The authors note the inclusion criterium ‘Research specific to IFM training as an intervention’ (line 66). As the authors mention, these muscles have a function many whole-body activities (e.g. walking), so arguably can be trained with many whole body activities as well (e.g. walking, running, whole body vibration training). How was IFM training defined for inclusion in the review?

5. No limitations were introduced to the search dates and yet only articles from after 2013 were included. This might just result from the novelty within the research field, but it could also indicate a fatal flawy in the search strategy. That is, it might be that the field evolved and that now different terms are used compared to 20 years ago. On example might be the following study: DOI: 10.1123/jsr.21.4.327. Please comment on this issue.

6. The authors state ‘When possible, the results of the included studies were pooled for meta-analysis using RevMan 5.3.’ (line 84). How was it determined whether this was possible? It would be helpful to inform the reader on this process. How come only 6 of the 15 papers ended up in the meta-analysis?

7. The prospero registration introduces the usage of the PEDro scale, in the methods section a ‘Checklist for Measuring Quality’ is introduced and in the results the Modified Downs and Black Quality Index is reported. Please resolve these inconsistencies and please specify why the prospero protocol was not adhered to.

MINOR ISSUES

1. The use of abbreviations drastically limits the readability of the manuscript. Following PLOS one author guidelines, the use of abbreviations should be limited, and non-standard abbreviations should not be used unless they appear at least three times in the text. While I believe that most abbreviations are used more than thrice, this is mainly through their use in table 2. I would advise to limit abbreviating terms in the main text and only use abbreviations in the table.

2. Line 22. I would suggest to use the term ‘effector’ rather than ‘organ’

3. Line 27. With the introduction of IFMs, I would advise to name which muscles are meant specifically.

4. Line 39-40. With introduction of the training methods, it would be helpful if the authors could explain in a bit more detail what these training methods are about and in particular where they are different from each other.

5. Line 65-66. “The remaining studies were then reviewed as full texts on the basis of the following criteria: …” - The present wording makes it appear like the title and abstract screening were based on different criteria. Please clarify whether this was the case.

6. Line 91-92. “After full text screening, one article as clinical pearl was excluded” – personally I am unfamiliar with the term ‘clinical pearl’ and why this should lead to exclusion. This might be just me, but in any case a bit further clarification might be helpful.

7. Line 135. Descriptive stats are only provided for runners. How about the non-runner participants?

8. Line 148-149. The information about intervention duration is duplicated after section 3.2 and does not need to be mentioned here.

9. Line 153. Please define extrinsic foot muscles.

10. Line 169. Please define CSA

11. Line 199. Please provide a more extensive/descriptive caption for figure 4.

12. Line 216. The authors mention advance technologies. Can they provide some example of such technologies?

13. Line 238. I believe this should be ‘though’ instead of ‘through’.

Reviewer #2: The goal of this manuscript was to develop a systematic review and a meta-analysis systematic review to identify the effect of intrinsic foot muscles training on foot function and dynamic postural balance.

The manuscript is relatively well grounded, it deals with a relevant topic to be investigated and deserves to be published. In its current state, the level of English throughout your manuscript need careful revision. I suggest a fluent English speaker read and correct grammatical, word choice, and syntax errors throughout the manuscript.

Although paper is straightforward but there are many suggestions/comments that I addressed throughout the manuscript.

There is a critical point in the methodology that is pooling data from studies that used different intervention approaches and time of intervention, and thus, the results are not expected to be the same. Pooling the data into a meta-analysis, it groups studies even if the results are not coming from the same approach of IFM training. Pooling data that came from different interventions, exercises and times of intervention and populations lead to huge heterogeneity that will certainly compromise a meta-analysis. It is pivotal to choose same interventions to be included in a meta-analysis and only then we could have an unbiased statistical analysis. This should be acknowledged and maybe exclude the meta-analysis from the manuscript. it does not add much as the only two variables that could be pooled did not achieve power enough to conclude anything robust.

Language issues examples (there are other weird sentences and word choices that need revision):

1. Please, consider reviewing the English language and grammar by a native reviewer. The writing compromises the understanding of parts of the manuscript.

2. Introduction: “Whilst running, the feet act as the starting body parts…” – correct to body PART.

3. Introduction: “Given that the feet are the most proximal aspect of the lower limb…”- correct to most DISTAL. The feet are distal and not proximal part of LL.

4. Introduction: “ground impact force (GRF)…” – correct to ground REACTION force.

5. Introduction: “During the early stance phase in running…” – correct to OF REARFOOT STRIKE running

6. Introduction: “… and providing better propulsion for runners in the swing phase [12].” – it provides better propulsion in the PUSH OFF phase, not swing phase!

Abstract and Introduction

1. Please, provide the PROSPERO registry number in the abstract.

2. At the end of the second paragraph of the introduction, the authors provide a closing sentence concluding all previous sentences, however it does not make sense. “Therefore, strengthening of IFMs has been suggested for the prevention and treatment of foot and ankle sports injuries [16].” The previous sentences describe all important roles of the foot and its intrinsic muscles, but they do not provide any evidence that strengthening the intrinsic foot muscles would prevent injuries. It is a fallacy and must be amended.

3. Line 39: Please consider including other papers that presented different foot muscle exercises program, as Matias et al. BMC Musculoskelet Disord. 2016 doi: 10.1186/s12891-016-1016-9. and Ferreira et al. Trials. 2020 doi: 10.1186/s13063-019-4017-9.

4. Lines 43-44 : “These factors are believed to protect runners from common running-related injuries [21, 23]…” it is an incorrect affirmation. Reference 21 does not “believe”, it proved that foot-related exercises do prevent RRI and reference 23 did not study RRI. Consider rephrasing the sentence.

5. Lines 47-48: “… and transmission efficiency of GRF.” What did the authors mean by efficiency GRF?! It does not make sense the way it is written. Please, rephrase the sentence.

6. Lines 48-49: “Nonetheless, current studies on IFM training are cross-sectional, and evidence to support this claim is lacking.” This sentence is also a fallacy. There are many papers that as RCT and not cross-sectional and those RCTs have proven the efficacy of the foot muscles training for several conditions Just to name two: Mølgaard CM, J Sci Med Sport. 2018 doi: 10.1016/j.jsams.2017.05.019. And your references 10 and 21, among other that need to be reviewed.

7. It is not clear what is the aim of this systematic review: look for RCTs, since the authors criticized that the majority of current studies are cross-sectional, or focuses on all types of studies. This need to be clear in the introduction.

8. The main question investigated in the review must be clearly posted in the introduction and it is not clear at all.

Methods

1. The type of studies that were searched and included need to be described in the search strategy.

2. What is a “desired foot biomechanics outcome” itemized in (2) in the Study selection session.

3. Please, specify better what “outcome characteristics” are in the data extraction session.

4. There is a critical point in the methodology that is pooling data from studies that used different intervention approaches and time of intervention, and thus, the results are not expected to be the same. Pooling the data into a meta-analysis, it groups studies even if the results are not coming from the same approach of IFM training. This should be acknowledged and maybe exclude the meta-analysis of the manuscript. Or, at least, include as a limitation of the meta-analysis performed.

5. Figure 1 need to clearly describe the reasons for excluding the 204 papers from the review.

Results

1. “one article as clinical pearl…” What the authors mean by that?

2. When describing the meta-analysis, the muscle volume that changed in one study did not appear and should at least be mentioned, not only the CSA, but muscle volume. The way it looks, readers will not know IFM changes foot muscles volume.

3. Please, correct Weight to body mass, because you express in kg.

4. Table 3 – include descriptions of abbreviations in the caption: FPI, COM, INT and BMI.

Discussion

1. Overall, the discussion is straightforward and focused, but the English language that needs revision.

2. Lines 208-216: it is important to emphasizes that the studies did see differences after the intervention in CSA and volume of the foot muscles. But the heterogeneous and critical meta-analysis performed did not detect any difference probably due to pooling papers with completely different interventions, exercises and times of intervention and populations.

3. The same comment above can be applied to third, fourth, fifth paragraphs of the discussion.

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Reviewer #1: No

Reviewer #2: No

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PONE-D-21-23366R1Effect of intrinsic foot muscles training on foot function and dynamic postural balance: A systematic review and meta-analysisPLOS ONE

Dear Dr. Wang,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. The language has to be cleaned up, before the paper can be further considered for publication.

Please submit your revised manuscript by Jan 23 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
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• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Peter Andreas Federolf

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: (No Response)

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

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4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: No

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: 1. Although most of the previous comments from this reviewer were addressed properly, the paper still needs improvement in language and flow. It is impossible to follow some new additions. I strongly recommend a professional service for proofreading, not only a colleague who is a native speaker, because it clearly did not work this time. The way the paper reads it is impossible to be fully understood.

2. I have used the search strategies now described in the paper and found some very important quality papers (PEDro scale 5 to 8) that were not included in this review. Additionally, I am familiar with many papers that used IFM training and it matched some of them that I found but is it no in this manuscript. I am listing below for the authors to consider including as it must not be out of your systematic review.

Missing relevant papers regarding you research question, your outcomes and your chosen study designs:

I. (PEDro score 7) Lee D-R, Choi Y-E. Effects of a 6-week intrinsic foot muscle exercise program on the functions of intrinsic foot muscle and dynamic balance in patients with chronic ankle instability. Journal of exercise rehabilitation. 2019;15(5):709.

Specifically, you cite this study but I did not understand why it was not included in your systematic review.

II. (PEDro score 5) Day EM, Hahn ME. Increased toe-flexor muscle strength does not alter metatarsophalangeal and ankle joint mechanics or running economy. Journal of sports sciences. 2019;37(23):2702-10.

III. (PEDro score 8) Jung D-Y, Koh E-K, Kwon O-Y. Effect of foot orthoses and short-foot exercise on the cross-sectional area of the abductor hallucis muscle in subjects with pes planus: a randomized controlled trial. Journal of back and musculoskeletal rehabilitation. 2011;24(4):225-31.

IV. (PEDro score 8) Kamonseki DH, Gonçalves GA, Liu CY, Júnior IL. Effect of stretching with and without muscle strengthening exercises for the foot and hip in patients with plantar fasciitis: a randomized controlled single-blind clinical trial. Manual therapy. 2016;23:76-82. (balance)

V. (PEDro score 6) Lynn SK, Padilla RA, Tsang KK. Differences in static-and dynamic-balance task performance after 4 weeks of intrinsic-foot-muscle training: the short-foot exercise versus the towel-curl exercise. Journal of sport rehabilitation. 2012;21(4):327-33.

3. There are two studies included that have a wrong year of publication. Please, correct it:

• Unver B, Erdem EU, Akbas E. Effects of Short-Foot Exercises on Fo 506 ot Posture, Pain, Disability and Plantar Pressure in Pes Planus. Journal of sport rehabilitation. 2019:1-16.

• Fraser JJ, Hertel J. Effects of a 4-week intrinsic foot muscle exercise program on motor function: a preliminary randomized control trial. Journal of sport rehabilitation. 2019;28(4):339-49.

4. In the PROSPERO registry, the risk of bias assessment is described as PEDro scale. However, in this manuscript the authors did no use this scale but the Modified Downs and Black Quality Index. Please resolve this inconsistency with your PROSPERO registry and specify why the PROSPERO protocol was not adhered to. The reviewer #1 had already pointed it out in the first review but it seems the authors did not understand it and have not explained this issue.

5. Ref 35 is listed as “Kim EK, Kim JS. 2016” As authors but in the evidence table, it is listed as “Eun-Kyung et al. (2016)” Please correct that.

6. Introduction Lines 53-54: ““Although numerous studies explore the effect of IFMs training, there is still lacking of evidence-based studies to review it systematically.” This sentence does not make sense. If there are many evidences, and it does indeed (you mentioned now in your paper) that proved the efficacy of the foot muscles training for several conditions, what exactly do you need? There is no “lacking evidenced-based studies”. On the contrary. What you really want is to review systematically the exiting evidences. Please, rephrase, again, the sentence.

7. Introduction Lines 66-67: “Randomized controlled trials, intervention studies, were eligible for inclusion.” What are intervention studies? Non-controlled studies? Case studies? Interrupted case series? Please, use the SIGN (Scottish Intercollegiate Guidelines Network) methodology to describe the type of studies that were searched and included in your review

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: Yes: Isabel C. N. Sacco

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PONE-D-21-23366R2Effect of intrinsic foot muscles training on foot function and dynamic postural balance: A systematic review and meta-analysisPLOS ONE

Dear Dr. Wang,

Thank you for submitting your manuscript to PLOS ONE.   

Your paper has been assessed by 2 reviewers of whom one is satisfied with the changes. The other reviewer still has several major and minor comments. 

I will allow one more revision. Please address the remaining issues carefully.

Please submit your revised manuscript by Mar 27 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Peter Andreas Federolf

Academic Editor

PLOS ONE

Additional Editor Comments:

Comments of Reviewer 2:

The authors have written an interesting review paper that, through the peer-review process so far has made some obvious progress. Still, some major issues remain, as well as numerous minor issues. Major issues lie in the reproducibility and complexity of the methods and results. Still significant steps are required in these sections before they would be fit for publication. Further, there needs to be a clear match between the results collected here and the conclusions of the study, as the discussion section currently reads like a narrative literature review, without adding much analyses to the reviewed studies (the analyses seem isolated in the results and are not clearly linked to the discussion).

I appreciate the further specification of the authors decision for using the Modified Downs and Black quality assessment to the manuscript. However, I do not feel the authors have sufficiently explained why they have neglected an a-priori established part of their protocol and chosen to use a different method. This undermines the credibility of the manuscript as one of the major strengths of a systematic review lies in the protocol that is established a-priori. As such, I would again ask the authors to explain in their response to reviewers letter why they made this decision.

Further comments in order of appearance.

Line 3-5. This sentence does not flow well due to the double use of the word ‘relevant’. I would suggest the following sentence: ‘Keywords related to IFM training were used to search four databases for relevant studies published between January 2011 and February 2021.’

Line 34-36. This sentence does not flow well as it is unclear how ‘they’ should be interpreted. I would suggest rephrasing to something starting with: ‘The main IFMs are … ‘

Line 45. So far this paragraph has been about running, but this final sentence switches the focus to walking. This breaks up the flow in the introduction.

Line 49-52. There is a flaw in the logic here. It cannot be stated that the part up until the first reference ‘[24]’ is proof for the part until the second reference ‘[23]’. These findings might be related, but proof is not offered by this statement.

Line 55-56. The aims statement does not flow logically from the previous. First, you state that much about the positive effects of IFM is already known. This is not a reason to study the concept further. A better rationale could be something along the lines of the following: ‘while a number of isolated studies have shown benefits of IFM, the applicability of these findings is still limited because, to date, no previous study has systematically studied these effects nor has a meta-analysis been applied to get an overall estimate of the effect of IFM training. Therefore, the current study aims…’

Line 72. Consider changing ‘in accordance with’ to ‘based on’

Line 74-75. Please specify here what ‘desired foot biomechanical parameters’ were

Line 80. Consider ‘i.e.’ to ‘e.g.’

Line 87-91. This statement is confusing and needs to be rephrased.

Line 92-97. It is clear that the mean difference was taken as an outcome measure. However, it is unclear what this difference is based on, related to the different designs included in the study. For instance with an RCT. Was the difference of the experimental group between pre and post test used, or the difference between experimental and control group at post test?

Line 170. Please report exact p values and associated tests statistics.

Line 170-172. This sentence reads like a concluding sentence and therefore does not fit the results section.

Line 178-180. The authors conclude here that the funnel plot shows a ‘slight asymmetry’. What was the basis for this classification? That is, as a rule of thumb, 10 observations are required to statistically assess the asymmetry of a funnel plot. Unless the authors are aware of other guidelines, I think caution is warranted in this interpretation step. Especially considering that if one would scale figure 4B to have a X axis from -6 to 6, the asymmetry would appear way more drastic.

Line 184. The Eun-Kyung (2016) reference is not represented in table 1 and 2.

Line 184-187. This figure needs a clearer caption. What do the values indicate? Especially the ‘total’ column is not clear. I initially interpreted this as the N of the studies, but if this is true, then there are inconsistencies with table 2.

Table 3. Please specify the meaning of ‘NR’

Line 225. Which hypothesis is meant here?

Discussion in general: this section reach much like a narrative review and the link to the quantitative results of this study should be emphasized.

Line 179. Consider using ‘supervisor’ rather than ‘supervisors’

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: No

Reviewer #2: Yes

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: The additions and corrections were properly executed and the paper sounds better in this version.

**********

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Reviewer #1: No

Reviewer #2: Yes: Isabel C N Sacco

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Effect of intrinsic foot muscles training on foot function and dynamic postural balance: A systematic review and meta-analysis

PONE-D-21-23366R3

Dear Dr. Wang,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: All of my previous comments have been addressed. To add one final comment: I would suggest adjusting the x-axes in figure 4 to have the same values in panel a and b. This will improve the readability and the reader's capability to compare both images.

**********

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If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: Yes: Steven van Andel