PONE-D-22-11086Stair ascent in postmenopausal women: A regression analysis exploring the relationships between walking speed and T-score with sagittal and frontal plane gait biomechanicsPLOS ONE

Dear Dr. Dostan,

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 have raised a number of questions related to the study design and statistical approach that need to be adequately addressed.

Please submit your revised manuscript by Oct 22 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,

John Leicester Williams, Ph.D.

Academic Editor

PLOS ONE

Journal requirements:

When submitting your revision, we need you to address these additional requirements.

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

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf.

2. We note that the grant information you provided in the ‘Funding Information’ and ‘Financial Disclosure’ sections do not match. When you resubmit, please ensure that you provide the correct grant numbers for the awards you received for your study in the ‘Funding Information’ section.

3. Thank you for stating the following in the Acknowledgments Section of your manuscript:

“We would like to thank and acknowledge Osteoporosis Research in East Yorkshire (OSPREY) (charity commission number: 1013289) who funded this research.”

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

Please remove any funding-related text from the manuscript and let us know how you would like to update your Funding Statement. Currently, your Funding Statement reads as follows:

“AD, CAD, NV received funding from Osteoporosis Research in East Yorkshire (OSPREY) (charity commission number: 1013289).

There are no grant number.

URL:https://www.osprey.org.uk/index.php

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.”

Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

4. In your Data Availability statement, you have not specified where the minimal data set underlying the results described in your manuscript can be found. PLOS defines a study's minimal data set as the underlying data used to reach the conclusions drawn in the manuscript and any additional data required to replicate the reported study findings in their entirety. All PLOS journals require that the minimal data set be made fully available. For more information about our data policy, please see http://journals.plos.org/plosone/s/data-availability.

Upon re-submitting your revised manuscript, please upload your study’s minimal underlying data set as either Supporting Information files or to a stable, public repository and include the relevant URLs, DOIs, or accession numbers within your revised cover letter. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories. Any potentially identifying patient information must be fully anonymized.

Important: If there are ethical or legal restrictions to sharing your data publicly, please explain these restrictions in detail. Please see our guidelines for more information on what we consider unacceptable restrictions to publicly sharing data: http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions. Note that it is not acceptable for the authors to be the sole named individuals responsible for ensuring data access.

We will update your Data Availability statement to reflect the information you provide in your cover letter.

5. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For more information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

In your revised cover letter, please address the following prompts:

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide.

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

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: Yes

**********

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

Reviewer #1: No

Reviewer #2: Yes

**********

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

**********

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

**********

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 manuscript examined the relationship between the gait related biomechanical variables and stair ascent speed and T-scores using multiple regression analyses. The study included relatively large number of participants. However, I have major reservations for the research question and analysis method of the regression model and variable selection method.

General comments –

1. The main hypothesis does not match the purpose of the student. It is well known that gait speed is highly correlated with many biomechanical gait variables. It is not worthwhile to investigate the relationship between the gait speed and gait related variables, even though it has not been explored extensively in the population as stated by the authors.

2. The regression analysis used in the study is sufficient enough to answer the research question. The inclusion of all variables (Tables 2-4) in the analyses are not appropriate without proper justifications as many of the included variables are more likely highly correlated with each other. Such an approach is not that different from running correlation coefficients among the variables. Correlation analysis is not sufficient in addressing the research question. More importantly, inclusion of all lower limb biomechanical variables and special and temporal gait variables in the analyses is too broad without focus. There are many stair gait biomechanical research studies and the authors should be able to draw sufficient information to narrow down the more important variables related to hip biomechanics that are more relevant to the hip fracture related to osteoporosis.

3. The gait speed determination was not provided in the method section but it was used as a main predictor of the regression models.

4. It seems that the authors included data from both limbs, trailing limb on the second step and leading limb in the third step, in their analysis. Did the authors used 10 individual trials and both limb’s data in the regression analysrs? This may inflate the sample size and violation of regression analysis as individual trials of the same condition for an individual participant are not considered independent of each other.

Specific comments –

Ln 74-76 The hypothesis is not a novel one as it is commonly known that gait speed is a main factor for changes in gait biomechanics, especially the gait kinetics.

Ln 84-85 the sample size is relatively small for the osteoporosis patients.

Ln 100-101 A picture of the stair system would be helpful.

Ln 105 It is important to have a consistent stair ascent speed. Did the authors monitor the speed?

Ln 105 Did the authors used the data of the average of 10 trials or data of the 10 dividual trials in the regression analyses? See also my general comment on this.

Ln 114 Change this to “Inverse dynamics analysis”.

Ln 118-121 It is not clear how the phases of stair ascent was defined. Later the authors referred to “pull-up” and “load rate” which were never mentioned that how there phases were defined. Although they referred to McFadyen and Winter (1988), but these should be defined in the methods.

Reviewer #2: General comments

The submitted manuscript is an observational study aimed at investigating the gait biomechanics of stair ascent for older, postmenopausal women. Forty-five women underwent DEXA to assessment bone health quality, and were subsequently categorised as either: healthy, osteopenic, or osteoporotic. On a separate occasion they then ascended aa five-step stair to capture kinematics and kinetics. Finally, regression analyses were conducted, revealing that gait speed was the most important characteristic in explaining variance in all biomechanical measures. T-score, or bone density score, explained variance for gait measures relating to dynamic stability, and has implications targeting the hip adductors and abductors, and core musculature for future exercise interventions for falls prevention in older women.

The study methodology is appropriate to satisfy the aims, the findings are original and would interest the journal’s readership.

Specific comments

Title

The title is currently verbose, and particularly throughout the manuscript, the use of ‘T-score’ may lose the reader. Although correct and scientific, many PLOS One readers from the natural and social sciences may not understand what T-score is without explanation.

Introduction

The aim could be written with greater clarity, and appears not to directly transfer to the aim stated in the abstract.

Methods

Participants

Page 4

I recommend presenting data for the measurement error associated with the DEXA scans. A minor point would also be to add the % proportion of ‘healthy’, ‘osteopenic’, etc.

You mention ‘strict criteria’ were used to exclude potential participants. However, the specific inclusion and exclusion criteria is not clearly stated, nor is there any information on whether i) any did not complete testing, ii) there were any adverse events (particularly trips), or iii) data was lost incomplete/lost for any participants. For the latter, if so, then what methods were used for data handling.

Protocol

Page 5

Consider including a pictorial / reproduction diagram of the stair set-up, including the gait cycle. This would benefit the paper in readability and help interpret the precise gait cycle.

Data analysis

Page 5

There is scant information on how joint moments and powers were calculated. Please expand on the inverse dynamic analyses. Also, the specific gait cycle could be better described, specifying the left / right foot contact for each gait phase.

Page 6

You give reference to McFadyen and Winter (1988), but there is no explanation of STA, H1, H2, etc, in the Method. These need succinctly adding.

Results

The results for joint power are not written in an accessible, easily interpretable manner. The use of H1, etc, do not really illustrate the gait cycle events. This subsection could be clearer.

Also, include exact P values and check that the significant variables highlighted in tables 2 and 3 are consistent with descriptions in the text.

Discussion

Page 12

I recommend briefly confirming whether limb length was an influential factor in step cadence and other temporo-spatial characteristics.

Page 113, line 222: “we recommend future studies quantify stair ascent speed…”, and based on the preceding sentence walking gait too.

Line 226: typo “level walk”

Line 241-244: It would be insightful to illustrate the trunk’s role in the ascent gait cycle (e.g. stance) for interpretation.

Page 15

The authors highlight the importance of physical activity in human gait in their limitations, but given there is a wealth of evidence to support those ‘highly’ physical active or ‘active’ in having greater gait ability, it is worth providing data on how many (n, %) were classified as: very active, active, low active, or sedentary.

**********

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.

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: James P. Gavin

**********

[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.

Relationship between stair ascent gait speed, bone density and gait characteristics of postmenopausal women

PONE-D-22-11086R1

Dear Dr. Dostan,

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 for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

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,

John Leicester Williams, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

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

**********

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

**********

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

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 #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 #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 #2: I commend the authors in their clear and logical responses to the reviewers. I feel they have adequately addressed the major and minor comments of the two reviewers.

**********

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: James P. Gavin

**********