PONE-D-21-00839

Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children’s Study (JECS-Y)

PLOS ONE

Dear Dr. Wako,

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.

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We look forward to receiving your revised manuscript.

Kind regards,

Tomoyoshi Komiyama, Ph.D

Academic Editor

PLOS ONE

Additional Editor Comments:

Dear Authors,

The authors results showed that FT is not directly related to retention of the standing posture in 396, 8-year-old children. The authors found a fairly high rate of FT in all participants and a higher FT score in the eyes-closed condition than in the eyes-open condition. Moreover, there were significant correlations between the FT score and the COP-path and COP-area. This is the first report on the relationship between FT and postural stability.

If these results become clear, I think your research is important for the future of clinicians and clinical researchers who aim to better understand FT.

However, I think that it is necessary to strengthen the reliability of the result by adding as much information as possible.

For that reason, I have some questions and concerns about the manuscript that you might consider.

I have attached the comments that reviewers have pointed out in your manuscript.

Two reviewer are critical to your manuscript.　

I think that the points suggested by these reviewers will be helpful in the revision.

In addition, I read your manuscript.

1. I think your research is good, but your methods are not clear enough for most readers to understand.

I strongly recommend the authors check and correct their manuscript.

2. I would like you to clearly describe how the clarification of this research will be useful in clinical practice.

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3. Please include your actual numerical p-values in Tables 3 and 4.

4. In your Methods section, please provide additional information about the participant recruitment method and the demographic details of your participants. Please ensure you have provided sufficient details to replicate the analyses such as:

a) a table of relevant demographic details,

b) a statement as to whether your sample can be considered representative of a larger population, and

c) a description of how participants were recruited.

5. Please provide a citation for The Japan Environment and Children’s Study.

6. One of the noted authors is a group or consortium [Japan Environment and Children’s Study

9 Group]. In addition to naming the author group, and listing the individual authors and affiliations within this group in the acknowledgments section of your manuscript, please also indicate clearly a lead author for this group along with a contact email address.

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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: Partly

Reviewer #2: Partly

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

Reviewer #1: Yes

Reviewer #2: Yes

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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: Yes

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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: This paper aims to clarify the prevalence of floating toe and its relationship with static postural stability in children. An objective evaluation is attempted by using a foot pressure plate. In conclusion, it was shown that the finger's contact with the ground is not directly related to postural stability but is more stable when the eyes are closed.

The following items are raised as questions in this paper's peer review, and the authors should clarify these questions.

For "Study design," why did the authors target only at the age of 8 in this study?

For "Test procedure and protocol", why did you compare COP-path and COP-area and use the measured value with the smaller COP-path for the analysis?

The authors cite J Phys Ther Sci, but the subject used here is an adult, and if it is adapted to children, it may be necessary to re-evaluate the parameters.

As for the FT score, the visual part is large, and it is necessary to show the definition when counting points.

Regarding the results, the values of men and women summed in Table 3 and Table 4, but what is the meaning of adding the significance of different qualities in the first place? If the total value is to be compared, it may be limited to the case of comparing all ages or comparing over time.

Regarding the discussion, the authors mentioned the difference in the central nervous system structure regarding the difference between men and women (line170-173). Still, it was explicitly caused by the difference between men and women in this study's central nervous system. It should be clarified whether or not it matches the data.

Line 173-182 suggests that the visual system precedes the vestibular system. The optical system is blocked when the eyes are closed, suggesting that the vestibular system's superiority over boys affects girls.

Neurologically, the static postural stability is controlled by the sensory nerve tract, the sensorimotor integration center, and the motor nerve tract.　In this respect, if it results only in the visual system and vestibular system pointed out by the authors, some scientific verification is necessary.

As mentioned above, at least the subjects should be targeted at a wider age group, and the research method should be reviewed, and the data should be interpreted again, such as improving the objectivity of the FT score and adding neuroscience experts to the research organization.

Reviewer #2: In this study, the relationship between floating toe and static postural stability in children is investigated through experiments.

Although it can be evaluated as a valuable achievement for many subjects, there are some parts that are difficult to understand and some parts that require additional explanation, so they are listed below.

I would like you to answer them appropriately.

If there are any misunderstandings or mistakes due to my lack of knowledge, please forgive me and report it as an answer to me.

1. At the end of the Abstract and in the Discussion section, the following are concluded: The results of this study show that contact between the toes and the ground is not directly related to static postural stability, but contributes to body stability during postural instability.

How will this result be used for future research and medical care?

2. Please correct the explanation of COP-path and COP-area so that the reader can understand it intuitively by using the example.

Also, please add the reason why the measurement time of 20 seconds was decided.

The reason why the shorter COP-path was used for the analysis in the two experiments is also unclear as it is.

Furthermore, I don't know if two experiments are enough.

Please add descriptions.

3. I can understand the definition of the explanation of FT score used in this study, but I do not understand its specific meaning, for example, why the thumb touches the ground at 2 points.

Please indicate the reason for deriving this definition.

In addition, it is said that there are other FT evaluation indexes, so please explain the relationship with them and the original points that are significantly different.

In the text, there are some descriptions such as FT rate and FTS.

Make sure it's different or that it's the same thing with a different name.

4. In the discussion, you said that the greater correlation between the FT score and the COP-path or COP-area when the eyes are closed is a result of the toes performing a function to stabilize the body.

But can't we interpret that instability is the cause of the toes' contact with the ground?

I think this is an important point, so please add a description.

5. "prevalence of floating toe" is included in the title.

Did you get any new insights into this?

In the discussion, it was written as the same as the previous reports, and I could not find a description of what was newly discovered.

6. It is very interesting that you are planning multifaceted research in the future, so please tell us specifically what kind of research results you can expect.

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6. 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.

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Reviewer #1: No

Reviewer #2: No

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Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children’s Study (JECS-Y)

PONE-D-21-00839R1

Dear Dr. Wako,

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.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Tomoyoshi Komiyama, Ph.D

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Dear author,

Thank you for submitting your revised manuscript.

I think it was much easier to understand than the original manuscript.

I am satisfied with the responses and the edits, I am happy to accept this manuscript.

The authors have replied to my remaining comments satisfactorily from two reviewers.

Therefore, I have no further comments to make, all of my previous concerns were adequately addressed.

This manuscript will be satiating the reader's interest.

Tomoyoshi Komiyama

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

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 #1: Yes

Reviewer #2: Yes

**********

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

**********

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

Reviewer #2: 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: The authors properly reflect the findings. By classifying men and women in Tables 3 and 4, the gender difference can be shown more clearly. Initially, the consideration of this difference was "difference in brain structure between men and women", but it has been corrected by appropriately.

Reviewer #2: I think you have responded appropriately to my comments in the previous peer review. Thank you very much.

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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 #1: No

Reviewer #2: Yes: NORIO TAGAWA