Comparison of External Load across Multi-Day Tournaments in Female Youth Volleyball Athletes
Christian Helland
Quincy Johnson
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsComments to author
General comments:
Thanks for doing the work of investigating and writing this interesting paper with the topic of external load measurements with wearable devices in team sports, that in the recent years, have been investigated more frequently. The external load for youth volleyball athletes across multi-day tournaments have on the other hand not been explored. Therefore, the findings of this paper could be of importance for practitioners in both training and match settings in volleyball. In the paper you conclude that there is no reduction in external load measurements (jumps, jump height and kinetic energy) over the 3 days period of match games. Would it be possible to see a reduction in internal load parameters, such as sRPE, HR, DOMS and TRIMP score? The holistic approach where you also discuss internal load measurement and the overall impact a multi-day tournament can have on the athlete is in my opinion of great interest. Pelzer et al 2020 (External training load and the effects on training response following three different training sessions in young elite beach volleyball players) is in my opinion a good example of combining these variables in beach volleyball.
You write that there are some studies showing that external load (number of jumps, jump height, kinetic energy) vary between player position, start vs. end of season and between more vs less competitive games. However, this has not been tested in youth volleyball over night tournament and not for setters that perform more jumps, in more sub maximal manners, than the other playing positions. Therefore, the purpose of this paper is of interest and a rather novel part of an interesting topic. I believe that many volleyball coaches find the kinetic energy at least as interesting as the jump measurers. It would be great to read a little more about this measure, the reliability, validity, and the movements behind the measure. What type of practical movements will increase or decrease this measure. In addition, I believe it could be explained more in detail how the measure is calculated.
In addition to these general comments, in the following specific comments I also provide some questions for reflection based on my own curiosity. These questions I hope help you see the paper from a reader’s perspective and may help the paper become even more readable.
Specific comments:
P.1 L.6: Abstract: should this be a heading?
P.1 L.8: Remove (2), or what does it mean?
P.1 L.10-11: Here you should specific the measurement device, or at least what type of technology you used.
P.1 L.11-12: Here it’s a little unclear to me if you used the average for a single match or the average of the average between matches.
P1 L12-14: Could you please describe the numbers? Is it the average, the lowest-highest, witch days or matches?
P.1 L.18-20: Why is it fewer physical demands early when the competition is more unequal? Shorter games, less movements, or the fact that it is less stressing to have a comfortable lead?
P1 L24: What movements is included in high-intensity energy expenditure? Jumps including one of these movements. Rephrase the sentence to describe a little more detailed.
P1 L30-31: In this sentence, is number of jumps the same as external load? If so, maybe you could provide some details. An even match = greater external load (number of jumps). Is it due to more sets played or because of longer sets?
P1 L41: what is a more competitive match? Explain in more detail please.
P2 L50: I find the reference (6) hard to find. Could you provide a little more detail about how they found slower contraction time peak power and jump height, and what they did to fatigue the athletes? I would be pleased to also read the paper; however, I can’t find it online.
P2 L81: What kind of other movement variables do you refer to here? Please specify? I believe Charlton et al. 2016 primarily looked at jump height and count in addition to proposing an algorithm for measure of load. Maybe Brooks et al 2021 (Quantifying jumps and external load in netball using VERT inertial measurement units) should be included as a reference?
P.2 l.86: Could you provide the calculations of these variables? Especially Kinetic energy, is this parameter validated?
P2 L88: Is the external load based on average per match? Have you considered the difference between number of sets per match? Would it be better to use an average per set played per day etc.?
Table 1: What type of jumps does the liberoes do during a match? I’m a bit surprised that they average around 12 jumps per game. Or maybe it is from the warmup. Could you provide a bit more context about the role of the libero in the introduction or in the method part. In addition, how many sets per game does the matches normally consist if? Best to 3 or 5 sets?
Figure 1: The abbreviation is difficult to read. Could you make the figure writings more readable?
P6 L158-159: Could you please elaborate around the reason why no potential differences in KE? What type of movement is then important? What do we miss if we only consider jumps and jump height?
P6 L179: Why can’t you look at the numbers from one game to another at the same day? I agree it might be interesting. Obviously, there may be more fatigue present due to shorter recovery time and no overnight recovery.
P6 L186-187: Again, what do they mean by claiming that competition increase near the end of the season? The teams play more equal skilled teams. So that the players must do more- and more intense work to hold their capacity level?
P6 L187-188: Why didn’t you measure subjective exertion etc.? Could you speculate that the RPE could decrease, in contrast to your findings on the objective measure of external load?
P7 L200: How do you suggest coaches can monitor between game recovery? This is a nice practical implication you are adding, so please elaborate. Du you also recommend all volleyball teams monitor external load with a device like VERT. Or is there a cheaper alternative solution to this type of monitoring?
P.7 l.228: Is the reference correctly cited?
Thanks for writing this interesting article and good luck with the future work!
Best regards!
Author Response
Reviewer #1
In the paper you conclude that there is no reduction in external load measurements (jumps, jump height and kinetic energy) over the 3 days period of match games. Would it be possible to see a reduction in internal load parameters, such as sRPE, HR, DOMS and TRIMP score? The holistic approach where you also discuss internal load measurement and the overall impact a multi-day tournament can have on the athlete is in my opinion of great interest. Pelzer et al 2020 (External training load and the effects on training response following three different training sessions in young elite beach volleyball players) is in my opinion a good example of combining these variables in beach volleyball.
Response: While we did not collect these measures, this is an excellent suggestion. We have added this suggestion to the final paragraph of the Discussion section, “Additionally, the present study did not collect any measures of internal workload (e.g., ratings of perceived exertion, heart rate, or training impulse). Future research should consider collecting these measures to provide a more holistic approach in assessing athlete workload and tolerance of the competition schedule.”
You write that there are some studies showing that external load (number of jumps, jump height, kinetic energy) vary between player position, start vs. end of season and between more vs less competitive games. However, this has not been tested in youth volleyball over night tournament and not for setters that perform more jumps, in more sub maximal manners, than the other playing positions. Therefore, the purpose of this paper is of interest and a rather novel part of an interesting topic. I believe that many volleyball coaches find the kinetic energy at least as interesting as the jump measurers. It would be great to read a little more about this measure, the reliability, validity, and the movements behind the measure. What type of practical movements will increase or decrease this measure. In addition, I believe it could be explained more in detail how the measure is calculated.
Response: Much more information about KE was added, including validation and considerations for use of the variable for comparison between jumping and non-jumping positions.
P.1 L.6: Abstract: should this be a heading?
Response: We have altered this to align with the journal requirements
P.1 L.8: Remove (2), or what does it mean?
Response: We have removed this, other numbers, and subheadings within the abstract
P.1 L.10-11: Here you should specify the measurement device, or at least what type of technology you used.
Response: Changed as requested. The sentence now reads as follows, “Workload was measured via kinetic energy (KE, J/lb), total jumps (TJ), high jumps (HJ, >51 cm), average jump height (cm), and percentage of high stress movements (%) via VERT accelerometers.”
P.1 L.11-12: Here it’s a little unclear to me if you used the average for a single match or the average of the average between matches.
Response: We have clarified as follows, “Data were analyzed across days and by position as an average per day.”
P1 L12-14: Could you please describe the numbers? Is it the average, the lowest-highest, which days or matches?
Response: Language was altered to clarify that these are ranges of the daily averages.
P.1 L.18-20: Why is it fewer physical demands early when the competition is more unequal? Shorter games, less movements, or the fact that it is less stressing to have a comfortable lead?
Response: Unfortunately, we are not able to provide further explanation in the abstract for this. However, we do provide an explanation in the final paragraph of the Discussion.
P1 L24: What movements are included in high-intensity energy expenditure? Jumps including one of these movements. Rephrase the sentence to describe a little more detailed.
Response: Details added as requested. The sentence reads as follows, “In volleyball, play consists of periods of short, high-intensity energy expenditure via jumping, sprinting, shuffling, and diving, followed by brief rest periods.”
P1 L30-31: In this sentence, is number of jumps the same as external load? If so, maybe you could provide some details. An even match = greater external load (number of jumps). Is it due to more sets played or because of longer sets?
Response: Clarification for external load was added. We do not know if this is due to longer rallies, more sets, or more points played as the previous literature did not explore that type of analysis.
P1 L41: what is a more competitive match? Explain in more detail please.
Response: Details were added. The sentence reads as follows, “Physiological data gathered on youth volleyball athletes in a high school volleyball season showed that match workload was the lowest in the beginning of the season and increased towards the end of the season during more competitive play with evenly matched opponents or when playoffs were at stake”
P2 L50: I find the reference (6) hard to find. Could you provide a little more detail about how they found slower contraction time peak power and jump height, and what they did to fatigue the athletes? I would be pleased to also read the paper; however, I can’t find it online.
Response: There was a citation error for this sentence, and it has been corrected. The correct citation is for the paper by Rodacki et al., and this has been corrected. Here is a link to my pdf copy of the paper by Vescovi et al. which has now been cited elsewhere, vescovi-vball jump characteristics II.pdf
P2 L81: What kind of other movement variables do you refer to here? Please specify? I believe Charlton et al. 2016 primarily looked at jump height and count in addition to proposing an algorithm for measure of load. Maybe Brooks et al 2021 (Quantifying jumps and external load in netball using VERT inertial measurement units) should be included as a reference?
Response: The Brooks article was added and “movement variables” was replaced with “kinetic energy.” This was a very helpful suggestion.
P.2 l.86: Could you provide the calculations of these variables? Especially Kinetic energy, is this parameter validated?
Response: Kinetic energy was shown to be a valid measure via Brooks et al. as noted in the previous comment. KE and Stress percentage are proprietary measures from VERT, and we have added the following statements on page 2, “TJ, HJ, and jump height use flight time for the calculation, but the exact algorithm is proprietary. The VERT calculation for KE is ½ Δv2, where v represents velocity (9), and stress % is calculated using the number of high surge movements relative to the total movements, but this algorithm is propriety to VERT.”
P2 L88: Is the external load based on average per match? Have you considered the difference between number of sets per match? Would it be better to use an average per set played per day etc.?
Response: Yes, the external load is presented as the average per match. We do not have confirmation of the total number of sets played per match for all of the data, so we are unable to analyze the data this way.
Table 1: What type of jumps does the liberoes do during a match? I’m a bit surprised that they average around 12 jumps per game. Or maybe it is from the warmup. Could you provide a bit more context about the role of the libero in the introduction or in the method part. In addition, how many sets per game does the matches normally consist if? Best to 3 or 5 sets?
Response: We have provided an explanation for the libero jumps in the second paragraph of the Discussion, “Liberos also registered mostly submaximal jumps, which most likely occurred during serving and celebratory activities.” The following statement was also added to the last part of section 3.3, “All matches were played in a best of three sets format.”
Figure 1: The abbreviation is difficult to read. Could you make the figure writings more readable?
Response: The font size on the figure has been increased for improved readability.
P6 L158-159: Could you please elaborate around the reason why no potential differences in KE? What type of movement is then important? What do we miss if we only consider jumps and jump height?
Response: The following was added regarding KE, “KE is considered a measure of total load, thus no positional differences suggests that athletes across jumping and non-jumping positions were moving and engaged in play. This variable has been shown to change similarly to jumping measurements across phases of a season in youth female volleyball players (5). KE may be a useful variable in assessing external load of athletes who do not engage in a high volume or jumping, and may be used for comparing workloads across positions.”
P6 L179: Why can’t you look at the numbers from one game to another at the same day? I agree it might be interesting. Obviously, there may be more fatigue present due to shorter recovery time and no overnight recovery.
Response: As previously stated, we do not have a confirmation on the number of sets played each day.
P6 L186-187: Again, what do they mean by claiming that competition increase near the end of the season? The teams play more equal skilled teams. So that the players must do more- and more intense work to hold their capacity level?
Response: The following statement was added to provide clarification, “The structure of the tournaments is designed such that the teams become more evenly matched with each day, and previous literature from other sports suggest that external workload increases with more evenly matched opponents (17,18).”
P6 L187-188: Why didn’t you measure subjective exertion etc.? Could you speculate that the RPE could decrease, in contrast to your findings on the objective measure of external load?
Response: With the volume of data collected and travel involved with this study, we were unable to get the athletes to comply with collecting subjective data. We have added this suggestion for future research in the last paragraph of the Discussion.
P7 L200: How do you suggest coaches can monitor between game recovery? This is a nice practical implication you are adding, so please elaborate. D you also recommend all volleyball teams monitor external load with a device like VERT. Or is there a cheaper alternative solution to this type of monitoring?
Response: The following statement was added, “Recovery should emphasize rest and healthy nutrition for the athlete and could include subjective assessments of athlete exertion and recovery.”
P.7 l.228: Is the reference correctly cited?
Response: This reference was corrected.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThere are several recommended revisions that are provided below for the authors to address:
Abstract:
Methods: If possible, please briefly describe the statistical analysis utilized within this investigation.
Conclusions: Within the first sentence, it may be beneficial to first state performance characteristics prior to potential recovery characteristics.
Introduction:
Overall, I believe that the introduction is well-written and adequately introduces the reader to the subject. No further revisions are requested at this time.
Methods:
2.1: If possible, please include IRB approval number.
2.2: Please include that participants were females within the first sentence.
Results and Discussion:
Overall, I believe that the results and discussion sections are well-written and adequately describes the findings to the reader. Furthermore, the tables and figures are clear, concise, and easy to understand. No further revisions are requested at this time.
Conclusions:
Based on the findings of this study, it may be worthwhile to dedicate one to two sentences that discuss the importance of physical preparation that ultimately supports sustained athletic performance within this population.
Author Response
Reviewer #2
Abstract, Methods: If possible, please briefly describe the statistical analysis utilized within this investigation.
Response: Added as requested, “Data were analyzed across days and by position as an average per day and analyzed via repeated measures analyses of variance.”
Abstract, Conclusions: Within the first sentence, it may be beneficial to first state performance characteristics prior to potential recovery characteristics.
Response: Added as requested, “Athletes appeared to perform and recover sufficiently between days of play such that their external load was not affected.”
Introduction: Overall, I believe that the introduction is well-written and adequately introduces the reader to the subject. No further revisions are requested at this time.
Response: Thank you.
Methods, 2.1: If possible, please include IRB approval number.
Response: Added as requested.
Methods, 2.2: Please include that participants were females within the first sentence.
Response: Added as requested.
Results and Discussion: Overall, I believe that the results and discussion sections are well-written and adequately describes the findings to the reader. Furthermore, the tables and figures are clear, concise, and easy to understand. No further revisions are requested at this time.
Response: Thank you.
Conclusions: Based on the findings of this study, it may be worthwhile to dedicate one to two sentences that discuss the importance of physical preparation that ultimately supports sustained athletic performance within this population.
Response: Thank you for this suggestion. Statements were added to the third paragraph of the Discussion as follows, “Recovery between days may also have been enhanced by the regular workload endured by the athletes. The annual and weekly schedule of youth volleyball athletes may have provided them with the physical preparation necessary for daily performance at this level (5,6).”
Author Response File: Author Response.pdf
