PONE-D-21-23457

Acute effects of the different relaxation periods during passive intermittent static stretching on arterial stiffness

PLOS ONE

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PLOS ONE

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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: Yes

Reviewer #2: Yes

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

Reviewer #1: No

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: No

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: The manuscript is focused on a interesting topic and could have some important practical implication.

The Authors tired to find the best relaxation period to optimise the vascular responsiveness (including measures of shear rare and arterial stiffness) of the tibial posterior artery after an unilateral passive stretching bout of the plantar flexor muscles.

The manuscript is on the whole well-written, the methods are technically sounding and the results adequately reported (although I suggest to use the exact P value and at least one measure of effect size to strengthen the results).

I still have some major questions the Authors should replied:

1) Please include and comment both in the Introduction and in the discussion a recent paper of Bisconti AV et al, J Phyisiol 2020 on this topic.

2) Was an a-prior sample size calculation performed for the two experimental set-up? if so, please include a paragraph.

3) Do the Authors feel that the Sit-and-Reach test would be sensitive enough to detect the changes in ROM after just an unilateral passives stretching bout of the plantar flexors? If not, the Authors should recognise that there is no parameter describing the stretch-induce change in ROM.

4) In the Discussion, please comment on the differences between your and Venturelli et al study.

Reviewer #2: The Authors studied the relationship between the relaxation period during stretching and the reduction of arterial stiffness, in healthy young men. In the first series of experiments they evaluated the changes in cardiac output, the shear rate in the posterior tibial artery and blood volume in the calf muscle during recovery (0-60 s) from a single bout of one-legged passive calf stretching. In the second series of experiments, they assessed the effects of different relaxation periods (5-, 10-, 20-, and 60-s) of passive one-legged intermittent calf stretching (30-s × 6 sets) on the femoral-ankle pulse wave velocity (faPWV) as an index of peripheral arterial stiffness. The results indicate that the stretched leg’s shear rate significantly increased from 0 to 10th s after stretching. The muscle blood volume in the stretched leg significantly decreased during stretching; then significantly increased during the recovery period after stretching. It was interesting that cardiac output remained unchanged during stretching and recovery. Moreover, the reduction in faPWV from the pre-stretching value in the stretched leg was significantly larger in the protocol with 10-s and 20-s relaxation periods than that in the non-stretched leg and in the 5-s and 60-s relaxation periods. The Authors suggest that the relaxation periods of intermittent static stretching causing a high transient increase in shear rate (via reperfusion after microvascular compression by the stretched calf muscles) are effective in reducing arterial stiffness. The study was well planned and the results are really interesting, demostrating that central hemodynamics are not really involved in the response to stretching in calf muscle arteries.

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Reviewer #1: No

Reviewer #2: No

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Acute effects of the different relaxation periods during passive intermittent static stretching on arterial stiffness

PONE-D-21-23457R1

Dear Dr. Iemitsu,

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.

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Kind regards,

Vincenzo Lionetti, M.D., PhD

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 #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: Yes

Reviewer #2: Yes

**********

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: The Authors replied satisfactorily to all my points. In my opinion no further revisions are required.

Reviewer #2: The paper has been improved and can be accepted for publication. The Authors prepared a new manuscript implemented and acceptable. The Authors explained their changes in the text and substantially improved their presentation 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: Yes: Emiliano Cè

Reviewer #2: No