Plyometric Performance in U13 Basketball: Influence of Modified Competitions and Maturational Status with GPS Tracking

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study “Plyometric Performance in U13 Basketball: Influence of Modified Competitions and Maturational Status with GPS Tracking”, analyses plyometric variables in two conditions of basketball games.

The study was well conducted, and the data analysis is well explained. Anyway, in order to clarify the readers «, I leave below some recommendations to improve the manuscript.

Pg. 2, ln. 53 and following: remove wrong format of inline citations like (Lloyd & Oliver, 2012). Review similar wrong inline citations in the manuscript according to journal rules.

Pg. 2, ln. 64-69: It is recommended to increase bibliographic research in the introduction section and discussion on the potential effects of altering the competition format, as this is the premise upon which the experimental design is based.

Pag. 3, ethical considerations: The authors did not present any authorization from an Ethical Committee to perform the study. No references to a collected informed consent, and no references to the compliance with the Declaration of Helsinki (World Medical Association, 2013), United Nations Convention on the Rights of the Child (1989) or others. This should be addressed in the Methods Section.

Pg. 3, ln. 104-106: What is the rationale of this modifications? If they were used in mini-basketball, why regress to the game format in higher ages? These prepositions must be explained coherently, connecting to the text in introduction.

Pg. 3, ln. 111-112: What is the meaning of “in bands”? Should be clarified in text.

Pg. 3, ln. 113: Why only in g-force in absolute values and not computed relative to weight forces? The differences observed may simply be due to the higher body weight of the more mature athletes.

Pg. 3, ln. 118-119: Further clarification should be added to understand which somatic maturation data was collected.

Pg. 3, ln. 119: Which protocol was used to assess anthropometric measurements? Who measured and which training the observer has, including intra- and inter-observer error?

Pg. 14, ln. 287: The risk of injuries and overload injuries are pointed out and is a real risk for this kind of population. Anyway, authors consider that the modified format of the competition should be considered, even with the increased impact related variables for almost all ages. Isn't that contradictory? Aren't the authors recommending a game format that could cause an increased risk of injury, potentially leading to players being sidelined for extended periods (in the case of overuse injuries) and promoting abandonment of basketball?

Pg. 14, ln. 299: Authors refer “… thereby promoting more equitable development across players with differing maturation rates”. However, the differences in %PATH not only persist, but also increase the differences between athletes with different maturation levels. This contradicts the hypothesis raised in the introductory section. Please clarify.

Author Response

Reviewer 1

Comments and Suggestions for Authors

The study “Plyometric Performance in U13 Basketball: Influence of Modified Competitions and Maturational Status with GPS Tracking”, analyses plyometric variables in two conditions of basketball games.

The study was well conducted, and the data analysis is well explained. Anyway, in order to clarify the readers «, I leave below some recommendations to improve the manuscript.

Pg. 2, ln. 53 and following: remove wrong format of inline citations like (Lloyd & Oliver, 2012). Review similar wrong inline citations in the manuscript according to journal rules.

 We removed. Thank you.

Pg. 2, ln. 64-69: It is recommended to increase bibliographic research in the introduction section and discussion on the potential effects of altering the competition format, as this is the premise upon which the experimental design is based.

The introduction it was increased were modified in accordance with your comments. Thank you for your comments.

Pag. 3, ethical considerations: The authors did not present any authorization from an Ethical Committee to perform the study. No references to a collected informed consent, and no references to the compliance with the Declaration of Helsinki (World Medical Association, 2013), United Nations Convention on the Rights of the Child (1989) or others. This should be addressed in the Methods Section.

We added this information. Thank you for your appreciation.

Pg. 3, ln. 104-106: What is the rationale of this modifications? If they were used in mini-basketball, why regress to the game format in higher ages? These prepositions must be explained coherently, connecting to the text in introduction.

From the U12 to the U13 stage, there is a regulatory leap. Players transition from minibasket to the official adult regulations. For this reason, an intermediate regulation was adopted: an intermediate hoop height was used, the minibasket three-point line was kept, and the senior 6.75m three-point line was introduced, but this line counts for 4 points.

We have attached the explanation that has been added to the article.

This regulation was chosen because it is an intermediate regulation between the preliminary stages and senior sport.

Pg. 3, ln. 111-112: What is the meaning of “in bands”? Should be clarified in text.

The authors have modified the term ‘bands’, replacing it with ‘zones’ to facilitate understanding. Thank you for your suggestion.

Pg. 3, ln. 113: Why only in g-force in absolute values and not computed relative to weight forces? The differences observed may simply be due to the higher body weight of the more mature athletes.

Most players had similar weights, so we decided not to perform this analysis based on weight.

We have attached the weight distribution.

Pg. 3, ln. 118-119: Further clarification should be added to understand which somatic maturation data was collected.

The text has been modified. Thank you for your correction.

Before the tournament, somatic maturation data were collected. Specifically, players’ body mass and standing height were measured, together with the height of both parents, using a Tanita stadiometer (Tanita BF-522W, Tokyo, Japan). All measurements were conducted in accordance with the standards set by the International Society for the Advancement of Kinanthropometry (ISAK) and were carried out by the same researcher, who is certified at ISAK Level 1. In addition, the date of birth and the date of the intervention were recorded. Based on these variables, maturational age was estimated through the percentage of predicted adult height (%PAH), calculated using the Khamis–Roche method [16,17]. This continuous %PAH variable was subsequently used to analyse how somatic maturation moderated the intervention.

Pg. 3, ln. 119: Which protocol was used to assess anthropometric measurements? Who measured and which training the observer has, including intra- and inter-observer error?

The authors have included information on the weight and height recording protocol

Before the tournament, somatic maturation data were collected. Specifically, players’ body mass and standing height were measured, together with the height of both parents, using a Tanita stadiometer (Tanita BF-522W, Tokyo, Japan). All measurements were conducted in accordance with the standards set by the International Society for the Advancement of Kinanthropometry (ISAK) and were carried out by the same researcher, who is certified at ISAK Level 1. In addition, the date of birth and the date of the intervention were recorded. Based on these variables, maturational age was estimated through the percentage of predicted adult height (%PAH), calculated using the Khamis–Roche method [16,17]. This continuous %PAH variable was subsequently used to analyse how somatic maturation moderated the intervention.

Pg. 14, ln. 287: The risk of injuries and overload injuries are pointed out and is a real risk for this kind of population. Anyway, authors consider that the modified format of the competition should be considered, even with the increased impact related variables for almost all ages. Isn't that contradictory? Aren't the authors recommending a game format that could cause an increased risk of injury, potentially leading to players being sidelined for extended periods (in the case of overuse injuries) and promoting abandonment of basketball?

The modified format may increase certain variables related to impact, although not to a level that makes it unsafe in itself. Furthermore, it is important to remember that most injuries in youth sports are caused by accumulated overload rather than just isolated impacts. In fact, during developmental stages, controlled exposure to mechanical loads and moderate impacts is necessary to promote the maturation, strengthening, and adaptation of bones, tendons, and other structures, as supported by the literature on youth training. Additionally, the authors highlight that the modified format offers pedagogical, developmental, and participation benefits, such as greater player engagement, more decisions per minute, and a higher number of ball contacts.

Pg. 14, ln. 299: Authors refer “… thereby promoting more equitable development across players with differing maturation rates”. However, the differences in %PATH not only persist, but also increase the differences between athletes with different maturation levels. This contradicts the hypothesis raised in the introductory section. Please clarify.

It has been clarified that this phrase refers to what happens in other sports.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The Introduction is relevant and effectively explains the  research problem. However, can the authors more explicitly define the gap in the current literature? Is it the lack of GPS tracking in modified games, or the failure to model maturity as a continuous variable? Additionally, ensure the hypotheses (e.g., modified competition reduces load disparity) are clearly stated and aligned with the statistical methods used (e.g., the moderation effect).

Design of the study is rigorous within-subjects design, where the same players participate in both the Standard Tournament (ST) and the Modified Tournament (MT). Moreover, the decision to model maturity using Percentage of Predicted Adult Height (%PAH) as a continuous moderator is methodologically advanced. However, the design would benefit if the authors can provide more details on the scheduling of the two tournaments.

Question for the authors: Was the order of participation randomized or counterbalanced?

Methods

The use of WIMU PRO™ GPS/IMU devices is excellent, providing objective, detailed kinematic data on impacts, steps, jumps, and G-force. The reliability and validity data for the specific WIMU plyometric metrics (e.g., G-force classification) should be provided or cited to ensure the high-magnitude impacts are accurately captured.

Question to the authors: What was the rationale for the 4-point rule, and how might this have specifically influenced players' plyometric activity compared to a simple reduction of court size?

Statistical analyses: The authors used appropriate statistics. However, the magnitude of the effect (Effect Size) is vital for practical interpretation by coaches.

Results. The results section is clear and well-structured, presenting data for all key metrics. Please include a measure of effect size (e.g., Cohen’s d ) for all significant findings to show how much the load changed.

The Discussion effectively interprets the complex findings, particularly how the MT differentially affected players based on maturity (e.g., more mature players increased high-magnitude load in the MT). The interpretation of the Bayesian factors demonstrates robust evidence for the core findings. However, authors should carefully re-evaluate the hypothesis that the MT reduced the disparity among players.

Question: For which variables was the disparity reduced, and for which was it amplified?

Are there any limitations of the study? The manuscript should clearly and explicitly acknowledge key limitations to provide a balanced perspective on the findings (e.g.: Short-Term design, Lack of Performance/Technical Data, etc.

Author Response

First of all, we would like to thank you for the time you have dedicated to reviewing our work. We will respond to each of your suggestions and make the corresponding changes in the document using red font.

Comments and Suggestions for Authors

The Introduction is relevant and effectively explains the  research problem. However, can the authors more explicitly define the gap in the current literature? Is it the lack of GPS tracking in modified games, or the failure to model maturity as a continuous variable? Additionally, ensure the hypotheses (e.g., modified competition reduces load disparity) are clearly stated and aligned with the statistical methods used (e.g., the moderation effect).

This information was added to the introduction section. Thank you.

Design of the study is rigorous within-subjects design, where the same players participate in both the Standard Tournament (ST) and the Modified Tournament (MT). Moreover, the decision to model maturity using Percentage of Predicted Adult Height (%PAH) as a continuous moderator is methodologically advanced. However, the design would benefit if the authors can provide more details on the scheduling of the two tournaments.

Question for the authors: Was the order of participation randomized or counterbalanced?

The order of participation was not randomised, but all players competed in both tournaments under similar conditions in terms of rest and organisation.

The logistics of the event (availability of facilities and schedule restrictions of the participating teams) prevented the order from being counterbalanced

Methods

The use of WIMU PRO™ GPS/IMU devices is excellent, providing objective, detailed kinematic data on impacts, steps, jumps, and G-force. The reliability and validity data for the specific WIMU plyometric metrics (e.g., G-force classification) should be provided or cited to ensure the high-magnitude impacts are accurately captured.

Gomez-Carmona, C. D., Bastida-Castillo, A., García-Rubio, J., Ibáñez, S. J., & Pino-Ortega, J. (2019). Static and dynamic reliability of WIMU PRO™ accelerometers according to anatomical placement. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, 233(2), 238-248.

Question to the authors: What was the rationale for the 4-point rule, and how might this have specifically influenced players' plyometric activity compared to a simple reduction of court size?

It was decided to implement an intermediate set of rules between youth basketball and senior basketball. In this regard, two distances were introduced: the 3-point line for mini-basketball (which is worth three points) and the 4-point line for senior basketball (which is worth four points).

Similarly, by implementing this 4-point line, the authors expected that defenses would create more space, allowing attackers to take more shots on the run. This should increase the number of jumps taken by both attackers and defenders during drives to the basket.

Statistical analyses: The authors used appropriate statistics. However, the magnitude of the effect (Effect Size) is vital for practical interpretation by coaches.

Results. The results section is clear and well-structured, presenting data for all key metrics. Please include a measure of effect size (e.g., Cohen’s d ) for all significant findings to show how much the load changed.

The authors have included the effect size in the wording of the results. Thank you for your appreciation.

The Discussion effectively interprets the complex findings, particularly how the MT differentially affected players based on maturity (e.g., more mature players increased high-magnitude load in the MT). The interpretation of the Bayesian factors demonstrates robust evidence for the core findings. However, authors should carefully re-evaluate the hypothesis that the MT reduced the disparity among players.

Question: For which variables was the disparity reduced, and for which was it amplified?

The authors have included:

In general terms, the results show that the Modified Tournament did not affect all variables uniformly. On the one hand, the disparity was reduced in variables associated with overall load, such as the total number of impacts or the number of steps during effective playing time, where inter-individual differences tended to narrow. However, the disparity clearly increased in variables related to high-magnitude plyometric load, such as landings in the 5–8G range and especially take-offs above 8G. This increase in variability was modulated by biological maturation, as more mature players showed much greater increases in playing time, horizontal impacts, and high-power actions.

Are there any limitations of the study? The manuscript should clearly and explicitly acknowledge key limitations to provide a balanced perspective on the findings (e.g.: Short-Term design, Lack of Performance/Technical Data, etc.

Some limitations have been included.

The study has some limitations, most notably the duration of the intervention. Therefore, it is necessary to explore the long-term effects of this intervention. Similarly, the subjects studied are young players, so it is necessary to analyze how it affects older and more experienced players.

Reviewer 3 Report

Comments and Suggestions for Authors

The following article presents a study of plyometric performance in Under-13s basketball, assessing the influence of modified competitions and maturity status using GPS tracking. Several gaps in the work mean that major revisions are required for it to pass the review process.

Introduction:

• Please expand the end of the introduction to provide a clearer explanation of the work's objective and its contribution to existing literature. Further comparisons with the literature would also be necessary, highlighting the limitations of the studies already conducted.

Materials and Methods:

•  For a better understanding of the content, subsection 2.1 could be renamed “Participants” or similar. It is also necessary to expand the subsection by explaining the inclusion/exclusion criteria. This section must include the ethics committee's acceptance of the measurement protocol. 
• Subsection 2.2 refers to Figure 1, but the description provided by the authors does not correspond to the figure cited. Perhaps the figure was not included? This subsection also requires improvement in terms of its description of the adopted protocol, which is very brief.
• Subsection 2.3 introduces measurement systems. While these are listed, no explanation is given as to where they are positioned, what parameters are set for the various acquisitions or what precautions have been taken to ensure reliable data can be obtained. While the instruments have been validated in a previous study, the authors should improve their description by including a diagram or image to help readers understand how these devices were used.
• Page 4, lines 140-143: present the scales more clearly, using a table or a system that is easier to read. 

Result

• Improve the results section, both in terms of the presentation of the figures, which are all very unclear, and the visualisation, paying attention to the numbers shown on the Cartesian axes. Try to reduce the number of digits used to represent the axes (see Figure 2). Furthermore, when there are multiple plots in a figure, authors are requested to include numbering, for example, or letters, e.g., Fig. 2a to Fig. 2b, and briefly explain the content in the caption.

Conclusion

• The conclusions are very short. However, this section needs to be expanded to highlight not only the results obtained, but also areas for improvement and potential future developments. Move future developments from the discussion section to the conclusions.

Author Response

First of all, we would like to thank you for the time you have dedicated to reviewing our work. We will respond to each of your suggestions and make the corresponding changes in the document using red font.

The English has been reviewed.

Comments and Suggestions for Authors

The following article presents a study of plyometric performance in Under-13s basketball, assessing the influence of modified competitions and maturity status using GPS tracking. Several gaps in the work mean that major revisions are required for it to pass the review process.

Introduction:

• Please expand the end of the introduction to provide a clearer explanation of the work's objective and its contribution to existing literature. Further comparisons with the literature would also be necessary, highlighting the limitations of the studies already conducted.

The introduction was expanded and comparisons with literature was introduced.   Thank you for your suggestion.

Materials and Methods:

• For a better understanding of the content, subsection 2.1 could be renamed “Participants” or similar. It is also necessary to expand the subsection by explaining the inclusion/exclusion criteria. This section must include the ethics committee's acceptance of the measurement protocol. 

The indicated changes have been made. Thank you for your contribution.

2.1 Participants

Forty-one under-13 male basketball players (mean age = 12.91 ± 0.57 years) from four teams in southeastern Spain were initially recruited. As selection criteria, players from the teams available during the data collection period were chosen. These players had to belong to federated teams, train three times per week, and participate in one competitive match. In addition, they were required to have a minimum of one year of playing experience. All were expected to complete pre-tournament assessments and participate in both the official and modified tournaments. Four players did not meet these requirements and were excluded, resulting in a final sample of 37 participants (n = 37). This sample size is consistent with previous studies in this field. All participants signed the informed consent form, and the study was approved by the Institutional Research Ethics Committee of the University of Murcia (No. 2828/2020).

• Subsection 2.2 refers to Figure 1, but the description provided by the authors does not correspond to the figure cited. Perhaps the figure was not included? This subsection also requires improvement in terms of its description of the adopted protocol, which is very brief.

The authors have modified the text. Thank you for your suggestion.

The study consisted of two competitive tournaments held over a single weekend. Each team played three matches per tournament following the same competitive structure (round-robin format, identical scheduling, and standardized warm-up procedures). This design ensured that performance comparisons between conditions were not influenced by differences in match order, rest time, or contextual factors.

On the first day, all games were conducted under the official under-14 rules of the FIBA. All players listed on the scoresheet were required to participate in at least one quarter within the first three, with a maximum of two consecutive quarters played. Substitutions were only allowed in cases of injury or disqualification due to five personal fouls. Match duration, court dimensions, ball size, and officiating criteria followed standard FEB guidelines.

On the second day, a tournament using modified rules (MT) was implemented. Basket height was reduced to 2.90 m, and the three-point area used in Spanish mini-basket competitions—a rectangular zone positioned 4 m from the basket—was adopted. Field goals attempted from beyond this line were awarded 3 points, while shots taken from the official 6.75 m distance were awarded 4 points. This rule set was selected because it represents an intermediate stage between the regulations applied at earlier developmental levels and those used in senior competition.

Across both days, teams were required to maintain the same roster and player rotation guidelines, and all matches were officiated by licensed referees. Warm-up duration, rest intervals between games, and data-collection procedures (tracking, performance indicators, and contextual information) were standardized to ensure comparability between competitive conditions. This regulation was chosen because it is an intermediate regulation between the preliminary stages and senior sport.

• Subsection 2.3 introduces measurement systems. While these are listed, no explanation is given as to where they are positioned, what parameters are set for the various acquisitions or what precautions have been taken to ensure reliable data can be obtained. While the instruments have been validated in a previous study, the authors should improve their description by including a diagram or image to help readers understand how these devices were used.

The authors have improved the explanation of the instruments.

To ensure the accuracy and reliability of data acquisition, all measurement systems were positioned and configured according to the manufacturer's recommendations and prior validation protocols. LPS (UWB-based) antennas were installed around the perimeter of the indoor court in a symmetrical rectangular configuration at a height of 3–4 m, ensuring complete coverage of the playing area and minimizing signal shadowing or occlusion. Each player wore the WIMU PRO™ device attached to a snug harness positioned between the shoulder blades. Data sampling rates were set to 1000 Hz for the IMU's inertial signals. To enhance reliability, all devices were powered on simultaneously, battery levels were checked before each match, and players were instructed not to adjust or tamper with the units during play. Figure 1 presents a diagram illustrating the antenna positions, the player-carrying unit, and the overall tracking setup to facilitate reproducibility and understanding of the instrumentation configuration.

• Page 4, lines 140-143: present the scales more clearly, using a table or a system that is easier to read. 
• We have included Table 1 to facilitate interpretation. Thank you for your contribution.

Result

• Improve the results section, both in terms of the presentation of the figures, which are all very unclear, and the visualisation, paying attention to the numbers shown on the Cartesian axes. Try to reduce the number of digits used to represent the axes (see Figure 2). Furthermore, when there are multiple plots in a figure, authors are requested to include numbering, for example, or letters, e.g., Fig. 2a to Fig. 2b, and briefly explain the content in the caption.

The figures are intended to show the points where mature age is a variable that moderates the intervention. The authors believe that the graphs are adequate for expressing this purpose.

The error in the axes of Figures 1 and 2 has been corrected.

The figures have been numbered as requested: 2a, 2b, etc.

Thank you for your contribution.

Conclusion

• The conclusions are very short. However, this section needs to be expanded to highlight not only the results obtained, but also areas for improvement and potential future developments. Move future developments from the discussion section to the conclusions.

This information has been moved to the conclusion Thank you for your feedback.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have responded to all the questions and made the suggested improvements to the work. The work can now proceed to publication.