The Effect of Caffeine Supplementation on Resistance and Jumping Exercise: The Interaction with CYP1A2 and ADORA2A Genotypes

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study was well designed and manuscript well written. 

I only have a few typographical errors and citation recommendations. 

 Lines 49 & 96: Erogenicity means something much different than intended. You likely mean ergogenicity.

 Line 127: Please include the reference for the ACSM criteria used for risk stratification.

 

Methods / Table 1: The gender distribution was not specified in this article. How many subjects were male? It should be easy to add this to Table 1 under the Age row. Authors could also utilize the same format as done with the SNPs and could provide specific n=#/n=# (male / female) overall and for each category.

Line 147: Include Ref 27 citation here as well for 1RM testing procedures.

Line 282: Is 715mg CAF dosage correct for the highest dosage administered?

Line 364: increase

Line 448: outcomes

Line 554: interpretation

Author Response

On behalf of all the authors, I wish to thank the reviewers for taking the time to critically appraise our manuscript.  We believe that addressing these points have made the manuscript stronger and we hope that it is acceptable for publication. 

 

Reviewer 1:

 

This study was well designed and manuscript well written. 

Thank you

I only have a few typographical errors and citation recommendations. 

 Lines 49 & 96: Erogenicity means something much different than intended. You likely mean ergogenicity.

We have edited to “ergogenics”

 Line 127: Please include the reference for the ACSM criteria used for risk stratification.

 Added.

Methods / Table 1: The gender distribution was not specified in this article. How many subjects were male? It should be easy to add this to Table 1 under the Age row. Authors could also utilize the same format as done with the SNPs and could provide specific n=#/n=# (male / female) overall and for each category.

We have added a line in the subjects and denoted that only males were included.

Line 147: Include Ref 27 citation here as well for 1RM testing procedures.

Added.

Line 282: Is 715mg CAF dosage correct for the highest dosage administered?

This is correct.  We had one subject who was quite large (6’4 and over 300 pounds)

Line 364: increase

Edited

Line 448: outcomes

Edited

Line 554: interpretation

Edited

Reviewer 2 Report

Comments and Suggestions for Authors

Firstly, thanks for inviting me to evaluate this paper. Although topic is too unique and needs much data in this topic, papers was written fastly and hard to follow, ın my opininon, it is a need to re-write whole paper within clarity. I give some suggestion which can be found in pdf version in attach.

 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

On behalf of all the authors, I wish to thank the reviewers for taking the time to critically appraise our manuscript.  We believe that addressing these points have made the manuscript stronger and we hope that it is acceptable for publication.

 

Reviewer 2:

moved this term to elsewhere

 

We have edited this to “cross-over design”

 

bench press during the first set and peak power in the second set

 

Edited, thank you.

 

provide also "low users'" results

 

Added.

 

give references to the end of sentence

 

Added.

 

there is no ambiguity regarding caf's effects on resistance exercise performance, there are a few "meta-analysis" that concluded caf improves significantly resistance exercise performance. revise this sentence. and concentrate more on "genotype" and "habitual caffeine intake level" in which  there is still ambiguity

 

Revised as suggested.

 

change the structure of this sentence, you cannot ask a question in intro

 

Revised as suggested

 

citation 21 is not on humans, delete reference 21, and reference 22 is too old to be cited. you can find below more recent two studies about habitual caffeine intake levels and exercise performance in humans that can be cited instead of reference 21 and 22

1-) Karayigit, R.; Aras, D. One week of low or moderate doses of caffeinated coffee consumption does not induce tolerance to the acute effects of caffeine on sprint performance. Eur. J. Hum. Mov. 2021, 47, 49–60.

2-) Grgic, J.; Mikulic, P. Acute effects of caffeine supplementation on resistance exercise, jumping, and Wingate performance: No influence of habitual caffeine intake. Eur. J. Sport Sci. 2020, 2, 1–11. 

 

We have deleted reference 21 and included the two references suggested.  However, we disagree that reference 22 (Bangsbo et al.) is less valid solely because of age.  This is an original piece of research, with appropriate methods and measurement tools, and human physiology has not changed in the last 2-3 decades.

 

are they men or women and how many of them men or women

 

The sample was males only, and this has been added.

 

confirm this number with power analysis

 

A power analysis has been added to the statistical analysis section

 

low users 

 

Edited accordingly

 

high users

 

Edited accordingly

 

what did you used to mask the bitter taste of caffeine ? 

 

Crystal light.  We have added this to the manuscript.

 

calculate the effect sizes and provide it

 

Effect sizes have been included, thank you for this suggestion.

 

whole discussion needs to be re-organized, to hard to read and follow. Please, look the papers that you cited as an example and re-write your discussion, in this style, it does not look scientific. Otherwise this paper cannot be published with this discussion. I invite all authors work on paper and read last version

 

We are unsure what areas of the discussion need to be reorganized or improved.  We discuss each outcome variable one at a time, place our findings in the context of the greater body of literature, and try to explain any discrepancies.  For novel findings, we attempt to provide mechanistic explanations and implications.  We do not see how this is organized any different than other research papers.

We deliberated between separating the study in multiple papers (1. genetics and metabolites, 2. outcomes and habituation), but ultimately felt it was more impactful to include all outcome variables in one paper, and that is why we chose to use subsections within the discussion.  The use of subsections in a discussion is not the norm, but it is also not uncommon for papers with several important outcome variables. We invite the reviewer to review the following papers which have also used sub-sections to organize their discussions, including one from this journal:

 

Caffeine Supplementation Strategies Among Endurance Athletes: https://pubmed.ncbi.nlm.nih.gov/35463835/

 

Neuroprotective Effects of Blueberries through Inhibition on Cholinesterase, Tyrosinase, Cyclooxygenase-2, and Amyloidogenesis: https://www.mdpi.com/1661-3821/3/1/4

 

Efficacy and Safety of Monacolin K Combined with Coenzyme Q10, Grape Seed, and Olive Leaf Extracts in Improving Lipid Profile of Patients with Mild-to-Moderate Hypercholesterolemia: A Self-Control StudyL: https://www.mdpi.com/1661-3821/3/1/1

 

what this studies says ?

 

We have added this information.

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

congrats !! now papers looks better.