-->PONE-D-25-54379-->-->Evaluating physiological responses and forward head-neck posture in primary students in Thailand when carrying nano and traditional backpacks-->-->PLOS One

Dear Dr. Punsawad,

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.

Please submit your revised manuscript by Apr 02 2026 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.

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• A 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.

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We look forward to receiving your revised manuscript.

Kind regards,

Tomoyoshi Komiyama, Ph.D

Academic Editor

PLOS One

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1.Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

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2. Thank you for stating the following financial disclosure:

“This project was funded by the National Science and Technology Development Agency (NSTDA) of Thailand and the Walailak University Graduate Research Fund (CGS-RF-2023/04).”

Please state what role the funders took in the study.  If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."

If this statement is not correct you must amend it as needed.

Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf.

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6. Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

Additional Editor Comments:

Dear authors,

Your study investigated the effects of traditional versus nano backpacks on physiological responses, head–neck posture, and discomfort in primary school children. Overall, nano bags were associated with better posture, lower physiological stress, and less discomfort, suggesting a safer alternative to reduce long-term musculoskeletal risk in children.

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

We thus have some questions and suggestions for the manuscript that you might consider. I believe these comments will be helpful in the revision of your study.

Tomoyoshi Komiyama

[Note: HTML markup is below. Please do not edit.]

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: Yes

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: 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

Reviewer #3: 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

Reviewer #3: 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: The paper does make a significance contribution on the field. Well done to researchers. These findings will assist scientists to develop strategies to combat the ill effects of backpack loading among children.

The paper is well written. The good flow regarding what the investigation aimed to review and the discussion of the findings.

I recommend paper for publication.

Reviewer #2: Overall, this manuscript represents a technically sound evaluation of the effects of a common backpack design in comparison to an intentionally-modified alternative, with unilateral vs bilateral carriage comparisons. To some degree, this nested design is redundant, given the plethora of previous literature indicating the effects of unilateral backpack carriage, but the results do not detract from the larger narrative and provide some validating overlap with previous publications.

I have two primary concerns with the manuscript in its current state:

(1) The use of the term "nano" bag only suggests a difference in size. Readers may therefore misunderstand the nuanced differences upon finding this manuscript in databases. I would recommend abandoning the "nano" moniker in the title for something more informative (or at least less singular in implication).

(2) The statistical methodology is somewhat unusual, due to the immediate assumption of a lack of normal distribution, and only pairwise analysis despite nested conditions (traditional vs nano and bilateral vs unilateral). The Wilcoxon test is conservative, undermining effective power due to the non-normal assumption, which may be unnecessary. I would recommend testing for normality, and then seriously considering a repeated measures ANOVA in order to determine the effects of each condition more precisely while controlling for multiple tests.

Tertiary comments:

- I appreciate the comprehensive, yet brief review in the introduction section.

- On line 165, you describe recording blood pressure measurements at 5-minute intervals, but describe 1-minute intervals on line 167.

- In the first paragraph of the discussion section, you describe potential effects associated with load carriage. This is somewhat confusing, as it implies a difference in load between the two backpacks, yet your methodology describes that these were both fixed at 10% body weight. Is it perhaps more valuable to explore the potential effects of the decreased moment arm of the load in the nano backpack due to the decreased thickness?

- The conclusion ultimately recommends the nano backpack design; I agree that results suggest this conclusion, but I recommend that the discussion section is used to better explore the design considerations that likely led to these positive outcomes, and then for the conclusion to recommend specific bag features instead of a product. I would also recommend including recommendations related to unilateral vs bilateral load carriage, given that it was a component of the study design and analysis.

Reviewer #3: This study compared nano and traditional bags in children aged 7–12 years. Nano bags were associated with lower physiological stress and less head–neck posture deviation than traditional bags, regardless of how they were worn. These results suggest that nano bags may reduce musculoskeletal risk during prolonged use. However, I have a few minor comments, which are outlined below.

There are slight discrepancies in the numerical values reported between the Results and the Discussion sections.

For example, regarding head tilt: in the Results (Lines 318–319 and Table 4), the values are 77.50° for the traditional bag and 72.85° for the nano bag (a difference of 4.65°), whereas in the Discussion (Lines 368–369), the head tilt with the traditional bag is reported as 78.60 ± 1.56° and described as an increase of approximately 5° compared with the nano bag.

This discrepancy may be due to the use of parametric statistics (e.g., mean ± standard deviation) in the Discussion. However, since the Methods section states that medians and interquartile ranges were used for analysis (Line 233), unifying the reported values to medians throughout the manuscript would help avoid reader confusion and improve statistical consistency.

In addition, in the Discussion of forward head posture, the manuscript states: “Additionally, forward head posture increased by 1 to 2 cm when using a traditional bag.” Given that the reported medians are 8.13 cm and 7.14 cm (a difference of 0.99 cm), it may be more consistent with the description of head tilt to express this as “approximately 1 cm.”

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

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-->

-->PONE-D-25-54379R1-->-->Evaluating physiological responses and forward head-neck posture in primary students in Thailand when carrying modified and traditional backpacks-->-->PLOS One

Dear Dr. Punsawad,

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.

Please submit your revised manuscript by May 14 2026 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 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.

As the corresponding author, your ORCID iD is verified in the submission system and will appear in the published article. PLOS supports the use of ORCID, and we encourage all coauthors to register for an ORCID iD and use it as well. Please encourage your coauthors to verify their ORCID iD within the submission system before final acceptance, as unverified ORCID iDs will not appear in the published article. Only the individual author can complete the verification step; PLOS staff cannot verify ORCID iDs on behalf of authors.

We look forward to receiving your revised manuscript.

Kind regards,

Tomoyoshi Komiyama, Ph.D

Academic Editor

PLOS One

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise.

Additional Editor Comments:

Dear authors,

Thank you for submitting your revised manuscript.

I think it is an improvement from the previous version.

However, one reviewer had additional questions.

This reviewer noticed some important information was missing,

so their judgement is major rather than minor revision.

Please answer these questions as listed below.

Tomoyoshi Komiyama

[Note: HTML markup is below. Please do not edit.]

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: All comments have been addressed

Reviewer #3: 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 #2: Yes

Reviewer #3: Partly

**********

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

Reviewer #2: Yes

Reviewer #3: No

**********

-->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

Reviewer #3: No

**********

-->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: Yes

Reviewer #3: 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 #2: I am satisfied with the revisions to the manuscript and appreciate the authors' efforts in the revision process.

Reviewer #3: Dear Authors,

Thank you very much for submitting your revised manuscript. However, I would greatly appreciate it if you could kindly address the following additional questions.

While the use of analysis of variance (ANOVA) is appropriate assuming the normality of the data, there are several critical issues regarding the reporting of statistical results and the presentation of data.

1. Statistical Analysis

The study employs repeated measures ANOVA; however, only the main effects are reported,

and the interaction effect (Bag type × number of straps) is missing. The authors should include the interaction statistics in the results and discuss whether the modified bag’s benefits depend on the carrying method.

2. Table Column Configuration

The study compares four specific conditions derived from the combination of Bag type (Traditional vs. Modified [Nano]) and Number of straps (Unilateral vs. Bilateral). In the current version (Revision 1), Tables 2, 3, 5, and 6 present "Traditional" and "Modified" in Columns 1 and 2, and "One strap" and "Two straps" in Columns 3 and 4. This layout is confusing as it appears to separate the factors rather than showing the combined experimental conditions. Considering the experimental conditions, it would be better to present the Mean and SD using the column configuration from the original version.

3. Inconsistencies in Statistical Reporting (P-values)

There is a highly concerning inconsistency in the reporting of p-values. The p-values presented in Table 2 and Table 3 for physiological responses are identical. Similarly, the p-values in Table 5 and Table 6 for head-neck posture are also identical. Statistically, the p-value for a Main Effect in a repeated measures ANOVA and the p-value for a post-hoc pairwise comparison should not be identical. This suggests that the results from the ANOVA may have been simply copied into the post-hoc tables, or that the post-hoc analysis was not performed correctly. Please clarify this and provide the correct, adjusted p-values for all pairwise comparisons.

4. Missing Table 4

The manuscript currently skips from Table 3 to Table 5. I suspect this is simply a clerical error in numbering, as there is no mention of a Table 4 in the text. Please renumber the subsequent tables and update the citations in the text.

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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: No

Reviewer #3: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

To ensure your figures meet our technical requirements, please review our figure guidelines: https://journals.plos.org/plosone/s/figures

You may also use PLOS’s free figure tool, NAAS, to help you prepare publication quality figures: https://journals.plos.org/plosone/s/figures#loc-tools-for-figure-preparation.

NAAS will assess whether your figures meet our technical requirements by comparing each figure against our figure specifications.

Evaluating physiological responses and forward head-neck posture in primary students in Thailand when carrying modified and traditional backpacks

PONE-D-25-54379R2

Dear Dr. Punsawad,

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.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support.

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 Authors,

Thank you for submitting your revised manuscript.

I found the revised version much easier to understand than the original manuscript.

I am satisfied with both the authors’ responses and the revisions made to the manuscript, and I am happy to recommend its acceptance.

The authors have addressed the remaining comments from all three reviewers satisfactorily.

Therefore, I have no further comments, and all of my previous concerns have been adequately resolved.

I believe this manuscript will be of considerable interest to readers.

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 #3: 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 #3: Yes

**********

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

Reviewer #3: 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 #3: 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 #3: 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 #3: Dear Authors,

I would like to commend the authors for their thorough revisions. The manuscript has been significantly improved through the inclusion of interaction effects and the reorganization of the tables, which have greatly enhanced the clarity and rigor of the analysis. The authors have fully addressed my concerns, and I believe the paper is now ready for publication.

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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 #3: No

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