Prediction of Percentage of Completed Repetitions to Failure Using Velocity Loss: Does the Relationship Remain Stable throughout a Training Session?
, Deniz Åžentürk 2, Zeki Akyildiz 3, Ivan Jukic 4,5 and Amador GarcÃa-Ramos 6,7,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsFirst off, I would like to commend the authors for their work in conducting this study and putting together this manuscript. Overall, I believe this is a very informative paper providing further explanation about the relationship between repetitions to failure and mean velocity. However, I feel that more research is needed before any definitive conclusions can be made about this relationship. Varying up the exercise, the percentage of one-repetition max, and the type of athlete being used (e.g., a high-volume lifter versus a high-load lifter.
Author Response
Please find enclosed a revision of our manuscript, “Velocity loss and percentage of completed repetitions to failure: does the relationship remain stable throughout a training session?”. We would like to thank you for giving us the opportunity to revise and improve our manuscript. We would also like to thank the reviewers for their thoughtful and constructive comments which have made the manuscript stronger. Changes to the original manuscript are highlighted in red font and an itemized point-by-point response to the reviewers’ comments is presented below.
AUTHORS’ RESPONSE TO THE REVIEWER 1
COMMENT
First off, I would like to commend the authors for their work in conducting this study and putting together this manuscript. Overall, I believe this is a very informative paper providing further explanation about the relationship between repetitions to failure and mean velocity. However, I feel that more research is needed before any definitive conclusions can be made about this relationship. Varying up the exercise, the percentage of one-repetition max, and the type of athlete being used (e.g., a high-volume lifter versus a high-load lifter.
RESPONSE
Thank you for acknowledging the contribution of our study to the literature on strength training prescription and velocity-based training. We completely agree with the reviewer that more research is needed as the topic of using lifting velocity to quantify proximity to failure is relatively new and therefore some methodological aspects remain to be investigated. In this sense, the following information is included in the last paragraph of the discussion where we encourage research to explore this relationship in other training conditions as suggested by the reviewer:
“First, similar to the vast majority of studies that have examined the %Rep-%VL relationships [5,6,15,16,24,25,27], our sample size consisted exclusively of resistance-training males and, therefore, the present findings might not transfer to female individuals or untrained individuals. Therefore, future studies should explore the goodness-of-fit and accuracy of %Rep-%VL relationships in female individuals. Second, we have explored the effect of fatigue on the accuracy of %Rep-%VL equations obtained during the parallel back-squat exercise against the 75%1RM load. Since the %Rep-%VL relationship is exercise- and load-dependent [6], further research is needed to confirm whether the present findings can be extrapolated to other loads and RT exercises. Finally, similar to previous studies [5,6,15,24], the use of a Smith machine may have limited the ecological validity of our findings for individuals using free-weights in their training programs. Although the accuracy of the %Rep-%VL equations is unlikely to improve when using free-weights, future studies should examine the pattern of repetition velocity decline during training sets performed to failure with free-weight exercises.”
Reviewer 2 Report
Comments and Suggestions for AuthorsAbout the introduction
It is characterized by discussion, citing and comparing findings from other studies. I would suggest making this part more objective and informative about the topic (not discussive).
Justify the object of the study. The reason for the study. However, do not argue based on a lack of research, but rather in relation to the gaps that surround the purpose of the study.
Line 86
The format mentioned by Sanches - Moreno fits into the discussion. In an introduction, only the numeral (in this case, in this journal) is used to indicate the reference.
About the methodology
Line 135: Why was 75% 1 RM determined for evaluation until failure? Based on any study? Is this the ideal percentage? I suggest referencing this parameter.
About results
Figures 2 and 3 are being presented in a very “polluted” way. This graph needs to be better presented. The reader will have a hard time interpreting the data. I notice that the lines that are drawn are obstructing all the kinetics of the data.
Discussion
The discussion is very redundant about the findings (repeating a lot of results). I would suggest exploring the cross-referencing of the data and, in addition, exposing some possible physiological and mechanical mechanisms (even if they have not been tested), to enrich the possible reasons for the result found.
In the conclusion, we can improve on the objectives of the study (mentioned at the end of the introduction, of which there are three). We could also describe more specifically the importance of the findings for practical use.
Author Response
Please find enclosed a revision of our manuscript, “Velocity loss and percentage of completed repetitions to failure: does the relationship remain stable throughout a training session?”. We would like to thank you for giving us the opportunity to revise and improve our manuscript. We would also like to thank the reviewers for their thoughtful and constructive comments which have made the manuscript stronger. Changes to the original manuscript are highlighted in red font and an itemized point-by-point response to the reviewers’ comments is presented below.
AUTHORS’ RESPONSE TO THE REVIEWER 2
COMMENT
About the introduction. It is characterized by discussion, citing and comparing findings from other studies. I would suggest making this part more objective and informative about the topic (not discussive).
RESPONSE
We appreciate the reviewer's suggestion. Several changes have been introduced in the introduction section to ensure it is more informative. Only in the third paragrapgh of the introduction more specific details are provided for prior research directly related to the variables examined in the current study. We believe it is important to be more detailed with these studies are their results are used to justify the original hypothesis of our study.
COMMENT
Justify the object of the study. The reason for the study. However, do not argue based on a lack of research, but rather in relation to the gaps that surround the purpose of the study.
RESPONSE
We agree with the reviewer. We have specified that the general reason of our study is “To address some gaps related to the use of %VL to quantify proximity to failure”.
COMMENT
Line 86. The format mentioned by Sanches - Moreno fits into the discussion. In an introduction, only the numeral (in this case, in this journal) is used to indicate the reference.
RESPONSE
We appreciate the reviewer's suggestion. We have verified that the suggested format for citations is followed throughout the introduction.
COMMENT
About the methodology. Line 135: Why was 75% 1 RM determined for evaluation until failure? Based on any study? Is this the ideal percentage? I suggest referencing this parameter.
RESPONSE
This is a pertinent comment. Although the ideal percentage would depend on training goals, we decided to select a relative load commonly used in strength training programs and also that has been frequently considered in scientific research exploring the viability of velocity loss to accurately predict the percentage of completed repetitions relative to the maximal number that can be achieved to failure. In this sense, the following sentence was added to the revised version of the manuscript: “The 75%1RM was selected because it is a relative load commonly used in RT programs and it has been previously considered in studies that have explored the properties of %Rep-%VL relationships [5,6,19].”
COMMENT
About results. Figures 2 and 3 are being presented in a very “polluted” way. This graph needs to be better presented. The reader will have a hard time interpreting the data. I notice that the lines that are drawn are obstructing all the kinetics of the data.
RESPONSE
We appreciate the reviewer's suggestion. However, note that nowadays it is a common trend to report the individual data in Figures of sport science papers as this contributes to increase the transparency of the data beyond the mere use of means and standard deviations (Hopkins et al., 2009). Indeed, the fact that the Figures seem “polluted” it is an interesting result itself, as it reveals the great variability between the conditions for the variables examined. The great dispersion in the lines reinforce our conclusions. Therefore, we opted to keep the individual data in the Figures at it provides valuable information regarding the behaviour of the variables in our study. The analysis of the individual data suggests that the low accuracy of %VL to predict proximity to failure is not cause by specific individuals. On the contrary, some individuals showed greater errors in one condition and others in other conditions, highlighting that the uncertainty of the data does not seem to be related to subjects´ characteristics.
Hopkins, W. G., Marshall, S. W., Batterham, A. M., & Hanin, J. (2009). Progressive statistics for studies in sports medicine and exercise science. Medicine and Science in Sports and Exercise, 41(1), 3–13. https://doi.org/10.1249/MSS.0b013e31818cb278
COMMENT
Discussion. The discussion is very redundant about the findings (repeating a lot of results). I would suggest exploring the cross-referencing of the data and, in addition, exposing some possible physiological and mechanical mechanisms (even if they have not been tested), to enrich the possible reasons for the result found.
RESPONSE
We appreciate the reviewer's suggestion. We have introduced several changes in the Discussion to not be redundant repeating our findings. Thank you for the suggestion.
COMMENT
In the conclusion, we can improve on the objectives of the study (mentioned at the end of the introduction, of which there are three). We could also describe more specifically the importance of the findings for practical use.
RESPONSE
We appreciate the reviewer's suggestion. Note that our study considered three objectives: (i) to compare the goodness-of-fit between the individual and general %Rep-%VL relationships obtained during a single set of repetitions to failure in the parallel back-squat exercise performed in a Smith machine against the 75%1RM load, (ii) to elucidate whether the general and individual %Rep-%VL relationships modelled from the data collected in the 1st set can provide accurate estimations of the %Rep when a moderate %VL is achieved during the successive sets (2nd, 3rd, and 4th sets) of the training session, and (iii) to determine whether the reference repetition (MVfastest specific to each set vs. MVfastest of the 1st set) used for computing the %VL affects the magnitude of the errors when estimating the %Rep.
The information provided in the conclusion sequentially answer each of our objectives:
Objective 1: “Individual %Rep-%VL relationships provided a better goodness-of-fit than the general %Rep-%VL relationship during the parallel back-squat exercise performed in a Smith machine against the 75%1RM load.”
Objective 2: However, regardless of whether the individual or general %Rep-%VL relationships are considered, the monitoring of %VL does not allow an accurate estimation of %Rep during a RT session consisting of multiple sets.
Objective 3: “MVfastest specific to each set should be recommended to obtain a more accurate estimation of the actual %Rep because the use of MVfastest of the 1st set could overestimate the %Rep when the successive sets are initiated in a fatigued condition. However, it is also important to note that using MVfastest specific to each set when the sets are initiated in a fatigued condition inevitably leads to individuals stopping the sets closer to failure when a fixed %VL is prescribed.”
Finally, the following sentence was added to summarize the practical importance of our findings: “These results do not support the use of %VL to accurately quantify proximity to failure during the Smith machine parallel back-squat exercise”.
