PONE-D-20-06221

Normative reference values of the handgrip strength for the Portuguese workers.

PLOS ONE

Dear Dr Bernardes

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We note that one or more of the authors are employed by a commercial company: Volkswagen Autoeuropa.

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Reviewer #1: Yes

Reviewer #2: No

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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?

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Reviewer #1: Yes

Reviewer #2: Yes

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

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Reviewer #1: Yes

Reviewer #2: No

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5. Review Comments to the Author

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

Reviewer #1: Dear Authors,

The research aimed to identify the normative values of handgrip strength for Portuguese workers in the automotive industry. The research has the potential to improve working conditions, prevent occupational disease, premature retirements and, consequently improve the quality of live for Portuguese workers.

Although the research is well written and the message is clear, minor adjustments are needed, which will be presented below:

Abstract: do not repeat the words that were used in the title as key terms.

Line 161: correct reference 9 (remove parentheses and inform author).

Results: The description of the sample was well done, but I missed the number of individuals per age group. I request that the authors add this information.

The results were well explored as text, however, the tables and figures can be improved.

Tables and figures:

Complement in the title the characteristics of the studied population: Portuguese women and men workers in the automotive industry.

Include the description of the abbreviation OR avoid abbreviation and include the complete nomenclature.

Include the number of people per group (“N”), when necessary.

Figures 3a and 3b: The figures are not clear, I suggest inserting the units of measurement of the scales.

The manuscript needs minor modifications before being accepted for publication. I hope that my suggestions contribute to improving the manuscript.

Sincerely.

Reviewer #2: The present study aimed to identify the normative values of handgrip strength for Portuguese workers in the automotive industry.

Abstract

Results: Please, verify age range for women regarding force declining. The abstract indicated force starting to declines for ages bellow the range that force reaches the peak … is it correct?

Conclusion: authors re-introduced the issue and suggested applications in very broad sense. Please, re-write the text according to the evidences of your results and make specific appointments concerning occupational care of Portuguese workers.

Introduction

The present study aimed “to identify the normative values of handgrip strength for Portuguese workers”. According to the authors, the assessment of strength level would support the diagnosis of muscle syndromes related to aging process (e.g.: frailty and sarcopenia), and handgrip scores is reliable to parametrize the development of syndromes affecting muscle ability to generate force accordingly. Moreover, authors included some paragraphs (apart of general introduction, which does not match PLOS One guidelines) to specify how different countries developed their own reference for handgrip strength.

However, author did not give enough information to support the theoretical link between handgrip scores of muscle force and muscle weakness/disability to perform a given occupational function. Furthermore, author fails to state the need to develop an index of force for each country, and the reasons for the lack of confidence in worldwide scores.

Methods

pp. 56 – 57: why to elect only workers from final assembly area?

pp. 60 – 65: text discussing the sample size. It is not appropriate in method section.

pp. 67-69: include the age range, numbers of workers, average weight and height for each age group.

pp. 70-74: include the numbers of participants excluded according each criteria.

p. 76: Methods (again?) …. Measurements (?)

pp. 114 – 117: identify the dependent parameter.

p. 115: OLS require alpha number to determine include and excluded variables.

pp. 120-122: support the choice of 1SD and 2SD to define cut-off values.

pp. 124 – 125: support the choice of 1SD to define risk threshold.

Results

pp. 131 – 140: describe the process of sample selection and should be located accordingly. Decimal cases should be separated by points.

pp. 141-144: I can’t observe differences in force values when compared the age groups for both female (Fig 1) and male (Fig 2). Did authors proceeded statistical test to compare force between groups?

All Figures should be revised. The units are not present, as well as, “Y” title.

p. 150: I am not sure that the term “decline” fits well to describe force profile variations between age groups. If authors considered such score the worsts, then force has not age as independent factor among females.

p. 163: revise kilograms symbol.

Figures 3a and 3b aren’t parts of the same figure.

Discussion

pp. 231-233: the findings are limited to the establishment of reference values. There is no results to confirm that workers having force values bellow the risk threshold presented sarcopenia or frailty syndrome. Please, revised this statement or support it better from your results.

pp. 236-237: This statement could not be corroborated from the results of Tables 1 and 2. Please, discuss it better.

p. 272: “malepopulation” means “male population”?

pp. 289 – 300: results for peak of force, force decrement, and cut-off points were just comment and not compared to others results from literature.

In discussion section, authors limited to explain differences regarding the references of force for handgrip test by comparing with others similar studies, or even reinforce main results. The applications to parametrize muscle syndromes and support occupational adjustments were discussed superficially.

Conclusion

pp. 304-309: author concluded about possible applications of the results. Most of these applications had no results to support the appointments. For example: (1) the ability to perform work above head was not related to handgrip force, and (2) the clinical relevance of handgrip force ability or disability to endorse worker relocation should be the proposition for future studies.

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Reviewer #1: No

Reviewer #2: No

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Normative reference values of the handgrip strength for the Portuguese workers.

PONE-D-20-06221R1

Dear Dra. Sarah Moreira Fernandes Bernardes

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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Anderson Saranz Zago, PhD

Academic Editor

PLOS ONE

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: All comments have been addressed

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

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

Reviewer #1: (No Response)

Reviewer #2: Yes

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

Reviewer #1: (No Response)

Reviewer #2: Yes

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

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

Reviewer #1: (No Response)

Reviewer #2: Yes

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

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

Reviewer #1: (No Response)

Reviewer #2: Yes

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6. Review Comments to the Author

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

Reviewer #1: (No Response)

Reviewer #2: Authors addressed all my previous comments and improved text, results and overall soundness of the manuscript.

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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: Dalton Müller Pessôa Filho