PONE-D-22-17503Associations of maximum and reactive strength indicators with force–velocity profiles obtained from squat jump and countermovement jumpPLOS ONE

Dear Dr. Nishioka,

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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: General Comments

The authors have sought to investigate the strength of relationship between a measure of maximal lower limb strength, and indicator of reactive strength quality and descriptive metrics of the force-velocity relationship obtained from squat jumps and countermovement jumps. The investigation has merit however I am concerned by the underlying assumption that the F-V relationship is linear when in fact it is curvilinear with an exponential decay from a maximum force at zero velocity down to zero force with a theoretical maximal velocity. Coupled with this issue is the fact that the authors have only tested each movement using two loads, an unloaded (bodyweight condition) and another with an external load of 40% 1RM with no justification for this loading condition or pattern. Interestingly the authors did perform a warm up across 4 different loading conditions but only at an 80% effort. The manuscript has been well written and it is clear that the authors have used an English language service.

Specific Comment

Ln14; Please change 'abilities' to 'properties'

Ln21; The section "...and drop jump (DJ) reactive strength index (RSI)." is confusing as it from my reading perspective it appears as if the authors calculated F-V profile information from the DJ as well which is not the case. Please re-word to clarify.

Ln37; Please change 'abilities' to 'properties'

Ln58;Please change 'abilities' to 'properties'

Ln65-67; This sentence is not a hypothesis and should be re-worded appropriately

Ln67; I have no issues with authors reanalysing published data to answer a new question, however this sentence is clumsily worded and should be re-worded.

Ln72; Change the word 'for' for 'across'

Ln74-77 and 188-193; This is a problematic flaw in the design of the investigation as measuring F-V properties from only two loads is not a comprehensive profile and negates the ability to determine whether the relationship is linear or not. The classical F-V relationship from isolated muscle fibres is a curvilinear relationship with an exponential decay. As such in multi-point movements, while the multifaceted characteristics of the muscle tendon unit may mask some of this curvilinear relationship a linear relationship should not be assumed. How certain are the authors that the relationship is linear? The authors need to justify relationship modelling choice, and the use of only 2 testing loads especially considering that the warm up protocol included 4 different loads.

Ln254; The discussion is likely to require a substantial re-write if changes are made to the choice of relationship model. The authors could also choose to report the relationship from actually recorded values rather than the calculated theoretical values which rely on the choice of model. Importantly it is these recorded values that any specifically undertaken training would change.

Figure 1, 2, 3 and 4; Please include the 95% CI for the line of best fit/regression when included

Reviewer #2: Congratulations for your work. Some concerns should be resolve before publication.

The short title doesn't talk about jump performance.

In your introduction you should talk about the term that you want to resolve with your research. Please rewrite this section giving more information about the F-v measurement importance.

In the first appearance should be stretch-shorting cycle (SSC). Review all the abbreviations throughout the manuscript and remember that abstract section is independent.

Line 78 What was the reason to have this range of hours?

Line 88: Delete mean ± SD

Line 107: rest (60-90 s)

Line 115: How and when did you estimate the individual RM?

Line 116: At the end of the warm up you were close to RM, it was this weigth used at the initial attemps?

Line 136: Why absolute value and not RM percentage?

Line 143: under the same environmental conditions

Line 203: What was the result of normality test?

Line 259: Explain here your hypothesis in relation with your results.

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Reviewer #1: Yes: Dale Wilson Chapman

Reviewer #2: No

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Attachments

Attachment

Submitted filename: TO AUTHORS.docx

Associations of maximum and reactive strength indicators with force–velocity profiles obtained from squat jump and countermovement jump

PONE-D-22-17503R1

Dear Dr. Nishioka,

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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Kind regards,

Javier Abián-Vicén, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

I'm going to accept the paper but the authors must correct the errors identified by reviewer 1 in figures 1, 2 and 4.

Fig 1; Check the SJ V0 and SJ Pmax panels as there are two p values

Fig 2; Check the SJ V0 and SJ Pmax panels as there are two p values

Fig 4; There are two p values provided in the V0 and Max panels?

Congratulations for your paper!

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: (No Response)

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: Yes

Reviewer #2: Yes

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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

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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: 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: I thank the authors for their comprehensive response to the initial review.

Fig 1; Check the SJ V0 and SJ Pmax panels as there are two p values

Fig 2; Check the SJ V0 and SJ Pmax panels as there are two p values

Fig 4; There are two p values provided in the V0 and Max panels?

Reviewer #2: Congratulations for your work agian. The manuscript has been improved and now has the quality to be published in PloSOne.

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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: Yes: Dale Wilson Chapman

Reviewer #2: No

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