Dear Dr. Liao,

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.

This paper was considered to be an appropriate study on resistance training, but it needs to be revised based on the comments from the experts. Please provide appropriate responses to the comments from the three reviewers.

Please submit your revised manuscript by Aug 29 2025 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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We look forward to receiving your revised manuscript.

Kind regards,

Tomohiro Yasuda, Ph.D.

Academic Editor

PLOS ONE

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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.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Partly

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2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #1: Partly

Reviewer #2: Partly

Reviewer #3: Partly

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3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: No

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4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

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Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #1: Overall Assessment:

This research protocol aim to investigate the effects of resistance training, vibration training, and their combination on sarcopenia, with a focus on both clinical outcomes and the intracellular IGF-1/PI3K/AKT/FOXO3 signaling axis, addresses a critical gap in the literature. The paucity of human-based evidence concerning these specific molecular pathways in the context of sarcopenia interventions significantly elevates its clinical and academic merit.

Specific Points of Review and Recommendations for Improvement:

1. Methodological Concerns Regarding Molecular Mechanism Elucidation:

The proposed timing of biopsy sample collection appears to be a limiting factor in fully elucidating the intricate molecular mechanisms underpinning the observed clinical effects. Without a more comprehensive sampling strategy (e.g., acute post-intervention time points or multiple time points throughout the intervention period), the study's capacity to precisely delineate the temporal molecular adaptations within the IGF-1/PI3K/AKT/FOXO3 axis remains ambiguous. A more detailed justification for the chosen biopsy time points, or a consideration of additional sampling, is warranted to strengthen the mechanistic insights.

2. Introduction:

Sex-Specific Considerations: The introduction lacks sufficient discussion regarding the known sex differences in sarcopenia prevalence, progression, and responsiveness to exercise interventions. Given the potential for differential responses, it is imperative to integrate relevant literature on sex-specific aspects and outline how these considerations will be addressed within the study design and subsequent analyses. This will enhance the generalizability and clinical relevance of the findings.

Elaboration on Vibration Training (VT) Molecular Mechanisms: The hypothesized molecular mechanisms by which vibration training impacts the IGF-1/PI3K/AKT/FOXO3 axis require more thorough substantiation. While general benefits of VT are often cited, a more detailed review of existing pre-clinical (e.g., animal models) and preliminary human studies that explore the cellular and molecular effects of VT on muscle anabolism and catabolism is necessary. This includes explicitly stating the proposed molecular cascade and formulating clear, testable hypotheses regarding VT's specific influence on the IGF-1/PI3K/AKT/FOXO3 axis.

3. Research Methods:

Design and Grouping – Justification for Intervention and Follow-up Durations: The rationale for the "12-week intervention" and "24-week follow-up" periods is not adequately articulated. A robust justification, grounded in existing literature on exercise physiology, sarcopenia intervention guidelines, or pilot data, is essential to validate these specific durations. This should include considerations for achieving meaningful physiological adaptations and assessing the sustainability of effects.

Sample Size Determination – Consideration of Sex: The current sample size calculation appears to lack consideration for potential sex-specific differences in outcome measures and intervention effects. If significant sex differences are anticipated in sarcopenia progression or response to interventions, the sample size calculation should either account for these variations or explicitly state the implications for generalizability across sexes. Stratification by sex or a power analysis informed by sex-specific variability would enhance the methodological rigor.

Inclusion Criteria – Management of Medication History: The inclusion criteria require more stringent attention to participants' medication history. Pharmacological agents known to influence muscle metabolism, inflammation, or hormonal balance (e.g., corticosteroids, specific cardiovascular medications, diabetes medications, etc.) could confound the study outcomes. A clear strategy for managing these potential confounding factors, whether through explicit exclusion criteria, precise documentation, or statistical adjustment in the analysis, must be elaborated.

Reviewer #2: The primary objective of this 2x2 factorial clinical trial is to evaluate the potential in vivo modulation of molecular mechanisms through combined resistance training (RT) and vibration training (VT) in patients with sarcopenia, and to determine the intervention’s impact on physical function. A total of 96 patients will be randomly allocated to one of four treatment arms: control, RT, VT, and RVT (combined RT and VT), with 24 patients per arm. The intervention period will last 12 weeks, and assessments will be conducted at baseline, after 12 weeks (post-intervention), and at 24 weeks (follow-up). Primary outcome measures include gait speed, handgrip strength, and skeletal muscle mass. Secondary outcome measures encompass IGF-1 concentrations, PI3K/AKT and FOXO3 protein activities, quality of life, and timed-up-and-go test performance. Although the authors discussed the statistical considerations, including the power analysis and sample size estimation, there are several major statistical concerns about this protocol.

Statistical critiques:

1. Although the authors provided a section on sample size determination, the information presented is superficial. The authors should explicitly clarify: (1) the specific statistical tests used for determining the sample size, (2) the anticipated effect sizes among the four treatment arms for each of the three primary endpoints, along with clinical justifications, (3) the identification of the primary measurement time point(s), considering assessments at both 12 and 24 weeks, (4) adjustment methods for the type I error rate, given the multiple comparisons arising from four treatment arms (six possible pairwise comparisons), three primary endpoints, and two assessment time points, and (5) whether an additive or synergistic effect between RT and VT is anticipated, as this significantly influences the power analysis and required sample size.

2. The authors need to clearly state the randomization method employed (e.g., simple randomization, permuted block randomization). Additionally, they should specify if any baseline variables will be used as stratification factors during randomization.

3. It is unclear why the authors did not propose using mixed-effects models for analyzing both primary and secondary outcomes. The authors should clarify their rationale for choosing alternative methods or consider adopting mixed-effects models to accommodate repeated measures and potential within-subject correlations.

4. The authors should explicitly specify the statistical methods intended for calculating 95% confidence intervals (CIs) for all primary and secondary endpoints.

5. The authors should state clearly whether the data analysis will follow an intention-to-treat approach or a modified intention-to-treat methodology.

6. The authors should clearly outline their strategy for multivariable data analysis, addressing the following aspects: (1) model performance evaluation, (2) assumption verification, (3) missing data handling, (4) adjustments for interaction terms and potential nonlinear relationships, and (5) methods planned for internal validation of the analytical model.

7. It is unclear whether the authors have considered including an interim analysis plan.

Reviewer #3: Preventing sarcopenia is a serious worldwide social issue. Resistance exercises are an evidence-based solution to this problem. If there is a way to increase the effectiveness of resistance exercises using a safe and/or low-cost manner, it should be challenged. The proposal in this article, written by Zhou H et al., is interesting from this point of view. However, content revisions and additional information are needed to make this proposal more understandable to the readers.

1) In community-dwelling elderly, the first screening to detect sarcopenia has been effective and recommended for physical function and muscle strength tests. However, loss of muscle mass is the most important indicator in the diagnosis. Therefore, muscle mass should be described before other indicators when describing sarcopenia in an academic article. For example, lines 26-27 (page 3), lines 39-40 (page 3), and line 49 (page 4) should bring the words “size” or “muscle mass” before the others.

2) Lines 50-52: The word “in China” should be included in the text because it is difficult to understand whether the 6.4% in men and 11.5% in women with sarcopenia are in China.

3) Lines 87-88: Correct the sentence as this sentence does not mean “delay the muscle function” but “delay the decline in muscle function”.

4) Lines 114 and 119: “Fig” at the beginning of a sentence should be written as “Figure”.

5) Line 183: Explain in detail the procedures and equipment that the authors plan to use to measure 1 RM.

6) Line 184 and S3 file: The authors plan to use TheraBands in training sessions, but it is unclear how to adjust the training load to 60% or 70% of 1 RM. Explain in detail how to adjust the load so that readers can understand.

7) Line 193: The term “chest depression” is not commonly used in training science. The term should be replaced with “chest press”.

8) Lines 202-203: If the VT consists of 4 sets of 1.5 minutes per session, with 1 minute of interval between the sets, the authors describe the total as 10 minutes (line 199), but isn’t 9 minutes the correct total?

9) Lines 184-185, 207-208: Why is it planned for the RT (70% of the 1 RM for the entire 12-week program) and RVT (50% of 1RM for the first 4 weeks, 55% of 1 RM for the second 4 weeks, and 60% of 1 RM for the final 4 weeks) groups to undergo resistance training at different exercise intensities? Given that the RVT group will be subjected to a lower intensity, any observed difference in training outcomes between the two groups may be confounded by this discrepancy, making it difficult to conclude whether the effects are attributable to training intensity or vibration stimulation. Would it not be more appropriate for both groups to be trained at the same resistance exercise intensity to ensure comparability? If differing training intensities are planned to be employed, the authors should explain scientifically the approach.

10) Lines 214-217: Why do the authors allow the control group to take educational courses? Education can cause behavioral changes in the control group, which may lead to lifestyle changes. Should the RT and RVT groups also take the educational courses? Add a rationalization that no matter what the research results of the study, having only the control group take the educational courses will not interfere with the interpretation of the research results.

11) Line 225: Revise “have sarcopenia” to “have probable sarcopenia” because decreased handgrip strength alone is not sarcopenia, but probable sarcopenia.

12) Lines 220, 228-231: Since the primary outcomes in the study include not only strength and performance (line 220) but also muscle mass (lines 228-231), the content of lines 228-231 should be included at the beginning (line 220).

13) Nutritional intake is also important in sarcopenia, but do the authors not plan to survey it? The authors should explain why the interpretation of the results would not be impaired if they are not done.

14) Revise “Gait speed (>1 m/s)” in Figure 2 to “Gait speed (<1 m/s)”.

15) S3 file, lines 2-3, English page 6: The following sentence is difficult to understand the meaning, “Each movement will be repeated 10 times, with 3 repetitions per set…”. Does “3 repetitions per set” in the sentence mean “3 sets per session”?

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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

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.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Dear Dr. Liao,

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.

==============================

Your research paper is currently being reviewed for publication, but it still needs further improvement. Please respond to the reviewers' comments appropriately.

==============================

Please submit your revised manuscript by Oct 03 2025 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.

• 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 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,

Tomohiro Yasuda, 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. 

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.

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

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: No

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #1: The authors have successfully addressed all of my previous comments. The manuscript is much improved, and I have no further concerns at this time.

Reviewer #2: The manuscript is much improved.

Reviewer #3: The revised manuscript by Zhou H et al. almost responded to my questions. However, there is one point that needs to be revised.

1) The authors revised that the educational sessions for the control group will not influence behaviors related to daily physical activity levels or nutritional intake in elderly people (lines 312 to 318). Many studies have reported that posters encouraging people of various ages to quit smoking are effective in promoting smoking cessation, and that posters encouraging exercise increase the physical activity levels people engage in. In this way, it has been shown that providing even a small amount of information can lead to behavioral change. Thus, it is difficult to interpret that the educational sessions for the elderly people, which consisted of two 60-minute classes per month on sarcopenia and health, will not promote behavioral change in elderly people. Previous studies showing that such educational interventions do not promote behavioral change, or even if they do, they do not result in improved muscle strength or physical function, should be presented. It is important to carefully evaluate the effects of educational sessions, as otherwise there is a risk of underestimating the value of physical training in other groups.

**********

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: 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.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org

Impacts of resistance training combined with vibration training on the IGF-1/PI3K/AKT/FOXO3 axis and clinical outcomes in patients with sarcopenia: A protocol for a randomized controlled trial

PONE-D-25-28564R2

Dear Dr. Yuanpeng Liao,

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,

Tomohiro Yasuda, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewer #2: None

Reviewer #3: None

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions?

Reviewer #2: Yes

Reviewer #3: Yes

**********

2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses??>

Reviewer #2: Yes

Reviewer #3: Yes

**********

3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable??>

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Have the authors described where all data underlying the findings will be made available when the study is complete??>

The PLOS Data policy

Reviewer #2: Yes

Reviewer #3: Yes

**********

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

Reviewer #2: Yes

Reviewer #3: Yes

**********

Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics.

You may also provide optional suggestions and comments to authors that they might find helpful in planning their study.

Reviewer #2: The authors have responded well to the statistical issues raised in the previous review. There is no further statistical concern about this revised manuscript.

Reviewer #3: The revised manuscript adequately addresses all points of concern and is acceptable. In my opinion, this article is worthy of publication in the PLoS ONE.

**********

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

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