Effect of 10-Week Plyometric Training on Anaerobic Performance and Biomechanical Properties of the Muscles in Football Players: Randomized Controlled Trial

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study is limited to amateur football players, which may restrict generalizability to athletes of different skill levels or disciplines. 

Including additional training modalities, such as resistance or eccentric training, alongside plyometric exercises could offer comparative insights into their respective effects on performance and biomechanics.

Although the study measured biomechanical properties, the lack of significant changes raises questions about the sensitivity of the methods used. To provide more granular insights, I suggest incorporating advanced imaging techniques or biochemical markers.

Author Response

The study is limited to amateur football players, which may restrict generalizability to athletes of different skill levels or disciplines. 

Including additional training modalities, such as resistance or eccentric training, alongside plyometric exercises could offer comparative insights into their respective effects on performance and biomechanics.

Although the study measured biomechanical properties, the lack of significant changes raises questions about the sensitivity of the methods used. To provide more granular insights, I suggest incorporating advanced imaging techniques or biochemical markers.

Response: Thank you for your suggestion.
While there are studies that support the reliability of the MyotonPRO device, we have not found many studies in the literature that demonstrate the use of myotonometry in long-term protocols, especially in plyometric training. Most studies using myoton are based on short-term effects. We assume that the fact that no statistically significant biomechanical changes were demonstrated may open new directions for research into why this is the case.

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for giving me the opportunity to review your manuscript. However, before it can be considered for acceptance, there are several critical points that should be addressed in advance.

L2-3: The title should be refined by shortening its length and clearly indicating the study design.

L18-19: In terms of p-value reporting, it is sufficient to state values as <0.05 or <0.01. Please implement this change throughout the manuscript, ensuring only two to three decimal places are used where appropriate.

L78-82: I respectfully disagree with this statement. There is substantial scientific evidence, including studies with larger sample sizes, on the effects of plyometric training in soccer players. In what way does this study differ from existing research, and why is it particularly noteworthy? This is a key concern that the authors should address more thoroughly in the Introduction.

L91-92. To fully understand your sample size calculation, I would appreciate further explanation regarding the justification for an effect size of 0.6 (e.g., based on relevant literature, previous studies, or pilot data), the type of statistical test used (Student’s t-test, ANOVA, etc.), the assumed variance, and whether the test is one-sided or two-sided. These details will facilitate a thorough evaluation of the methodological coherence of your study.

L94. Please indicate the units for BMI and training experience.

L95. Indicate de sex of the players

L96. Why were the inclusion criteria set at 16 to 38 years of age? On what basis was this decision made? Please clarify in the manuscript.

L107. In the “Study Design” section, you have included information that was already addressed earlier in the manuscript. Please remove or revise this content to avoid redundancy.

L120 and L123. The group sizes were already indicated previously. Kindly remove “n=10)” to avoid redundancy.

L131. Do the authors consider HRmax an appropriate method for monitoring intensity in a plyometric training program? On what basis has this decision been made? I believe that not taking other parameters, such as RPE, into account represents a limitation that should be acknowledged.

L244. The format of Table 4 could be improved to provide more information for the reader. Please indicate both inter-group and intra-group differences in Table 4, perhaps by using symbols or adding additional columns.

L300. Please refine the format of Figure 12 to enhance clarity and facilitate better interpretation.

Author Response

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

 

Comment 1: L2-3: The title should be refined by shortening its length and clearly indicating the study design.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore we have shortened the title [L2-3]

Comment 2: L18-19: In terms of p-value reporting, it is sufficient to state values as <0.05 or <0.01. Please implement this change throughout the manuscript, ensuring only two to three decimal places are used where appropriate.

 

Response 1: Thank you for pointing this out, the suggestions have been implemented

Comment 3: L78-82: I respectfully disagree with this statement. There is substantial scientific evidence, including studies with larger sample sizes, on the effects of plyometric training in soccer players. In what way does this study differ from existing research, and why is it particularly noteworthy? This is a key concern that the authors should address more thoroughly in the Introduction.

Response 1: Thank you for pointing this out. I agree with this comment. Therefore we have removed these sentences and made some changes. Our study was unique because we used the myoton device for measurements - which certainly has its limitations, but can be an indicator for further research into biomechanical changes in muscles after specific training interventions using this device. In addition, we created a strictly 10-week plan, which can be effective compromise for amateur footballers who have a winter break in our country, where the games end around December, return to training in January and start the league games in March.

 

Comment 4: L91-92. To fully understand your sample size calculation, I would appreciate further explanation regarding the justification for an effect size of 0.6 (e.g., based on relevant literature, previous studies, or pilot data), the type of statistical test used (Student’s t-test, ANOVA, etc.), the assumed variance, and whether the test is one-sided or two-sided. These details will facilitate a thorough evaluation of the methodological coherence of your study.

Response 1: The sample size calculation was conducted for a one-way repeated-measures ANOVA, with an alpha level set at 0.05 and a power (1-β) of 0.96. The effect size was determined based on relevant literature, assuming moderate variability in performance metrics within this population. We have clarified that the test was two-sided. To justify the use of ES = 0.6  (Cohen, f; equivalent to η2 = 0.14, because we use it later) in our sample size calculation, we based our selection on values reported in previous studies examining the effects of plyometric training on athletic performance metrics. For example : DOI:10.3389/fphys.2019.01026. ES = 0.6 was also used to achieve moderate to large effects to increase the value of study. Do not misidentify with ES for two group differences (d Cohen) used after post hoc tests.

 

Comment 5: L94. Please indicate the units for BMI and training experience.

Response 1: Thank you for pointing this out. We have indicated the units. [L96]

 

Comment 6: L95. Indicate de sex of the players

Response 1: Thank you for pointing this out. We have indicated the sex of the players. [L94]

 

Comment 7: L96. Why were the inclusion criteria set at 16 to 38 years of age? On what basis was this decision made? Please clarify in the manuscript.

Response 1: Thank you for pointing this out. We have explained it in manuscript. [L99-101]

 

Comment 8: L107. In the “Study Design” section, you have included information that was already addressed earlier in the manuscript. Please remove or revise this content to avoid redundancy.

Response 1: Thank you for pointing this out. We have removed this content. [L113-115]

 

Comment 9: L120 and L123. The group sizes were already indicated previously. Kindly remove “n=10)” to avoid redundancy.

Response 1: Thank you for pointing this out. We have removed this content. [L113-115]

 

Comment 10: L131. Do the authors consider HRmax an appropriate method for monitoring intensity in a plyometric training program? On what basis has this decision been made? I believe that not taking other parameters, such as RPE, into account represents a limitation that should be acknowledged.

Response 1: Thank you for pointing this out. During training, each competitor is equipped with a watch that measures their heart rate, this was our way of monitoring their readiness to perform the next jumps. We firmly believe that 2-minute breaks between each series are essential for maintaining maximum intensity for each jump. This duration provides adequate time for athletes to rest and lower their heart rates effectively. None of the athletes have reported any issues with the break length, but we were prepared to revise the protocol if necessary.

Response 2: We found an error in the text, in the end the break between each series was 120 seconds just like it is shown in the table, not 120-60s. I removed it from manuscript and mentioned watches. [L133-135]

Comment 11: L244. The format of Table 4 could be improved to provide more information for the reader. Please indicate both inter-group and intra-group differences in Table 4, perhaps by using symbols or adding additional columns.

Response 1: Thank for the taking the notice. The information is provided via symbols explained in a footnote. [L249-251]

Comment 12: L300. Please refine the format of Figure 12 to enhance clarity and facilitate better interpretation.

Response 1: Thank you for pointing this out. We divided Figure 12 into 3 smaller ones, they should be more legible. [L304-310]