Influence of Category and Sex in Game Structure Variables in Young Elite Tennis

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study analyzed the temporal and formal structures of tennis for U-12 and U-14 categories. The study design is sound. My primary criticisms are related to a lack of critical analysis of the results. I have outlined specific details below.

Abstract:

1. Please add study purpose if there is space in the word/character count.

Intro:

1. Overall, this section is a bit verbose. Please consider adding a table with the data outlined in this section. This would likely cut back on word count and make it easy for comparison of your results later on.

Methods:

1. Participants: please provide a breakdown of the n-sizes per sex and age group.
2. As data were collected across multiple tournaments, is there a chance that there were repeated measures of certain participants? If so, this should be disclosed and accounted for statistically.
3. Table 1 seems unnecessary 
4. Table 3: typo in the last column heading; change strenght to strength
5. Statistical analysis: please provide more details regarding the one-way ANOVA. Was this compared for U-12 boys, U-12 girls, U-14 boys, and U-14 girls? Please provide sufficient details such that this could be repeated.
6. Provide guidelines for interpretations of Cramer's V, Cohen's d, and partial eta-squared.

Results:

1. Provide main effect results first

Discussion:

1. This section compared the results of the present study to that of previous research, but without any speculation regarding differences or similarities in results. Please provide some context for why you think your results turned out they way they did. Some of this can be found in the Conclusion section, but there's more discussion needed to explain why the results turned out this way.

Author Response

Before I begin responding to each of your comments in the review, I would like to thank you for your attention and dedication in helping me improve the development of the article. 

ABSTRACT
Comment 1: 
Please add study purpose if there is space in the word/character count.

Response 1:
We agree with this comment as it helps to improve the focus on the study’s purpose, therefore despite the limited word count allowed in the abstract, we have highlighted the purpose of the study in the statement: ''This study examined the effects of sex and age category on the temporal and formal structure of play in youth tennis.''

INTRO:
Comment 1: 
Overall, this section is a bit verbose. Please consider adding a table with the data outlined in this section. This would likely cut back on word count and make it easy for comparison of your results later on.

Response 1: 
Thank you for pointing out the lack of synthesis and clarity in the presentation of the results, as reading through the entire section may indeed be confusing due to the large number of variables included. Therefore, I have created Table 1, in which I also provide details on the sample characteristics of the reviewed articles.

METHODS: 
Comment 1: 
Participants: please provide a breakdown of the n-sizes per sex and age group.

Response 1: 
Thank you for your concern regarding the specific sample. Therefore, I have included Table 2, in which I specify the players and the corresponding variables related to them.

Comment 2: 
As data were collected across multiple tournaments, is there a chance that there were repeated measures of certain participants? If so, this should be disclosed and accounted for statistically.

Response 2: 
No player was repeated across the tournaments, as these events correspond to age-specific competitions that players have only one opportunity to participate in during their sporting development. 

Comment 3: 
Table 1 seems unnecessary 

Response 3: 
Thank you for the observation, as it helps to avoid overloading the text with unnecessary tables. In this case, the information has been detailed in lines 135 and 136 through the statement: 'to age (U-12 and U-14) and gender (male and female). 

Comment 4: 
Table 3: typo in the last column heading; change strenght to strength

Response 4: 
Changed, thank you for the observation.

Comment 5: 
Statistical analysis: please provide more details regarding the one-way ANOVA. Was this compared for U-12 boys, U-12 girls, U-14 boys, and U-14 girls? Please provide sufficient details such that this could be repeated.

Response 5: 
Thank you very much for your contribution:
- For the dependent variables that showed a normal distribution and homogeneity of variances, two-way ANOVA tests (gender, age category) were conducted to analyze the effect of gender, category, and their interaction. Post-hoc tests were requested using the Bonferroni correction.

- The results and statistical analysis sections have been rewritten. The results table now also displays the main effects, in addition to the revised presentation of the results.

- Moreover, the SPSS databases used in the analysis have been attached to facilitate reproducibility. These include:

• • The “DATOS O1” database, which was used for calculating the results of the variables: Total match time (min), Total set time (min), Total game time (s), Duration of point (s), Pecentage of active match time. 

  • The “DATOS O 2.1, 2.2, and 2.3” database, which was used for calculating the results of the following variables: Number of sets per match, Number of games per set, Number of points per game. 

  • The “DATOS O 2.4 and 2.5” database, which was used for calculating the results of the variable: Number of hits per point. 

  • The “FINAL_Frecuencia_Partido” database, which was used for calculating the results of the variable: Frequency per match (strokes/min)

Comment 5: 
Provide guidelines for interpretations of Cramer's V, Cohen's d, and partial eta-squared.

Response 5: 

Thank you for your comment. Please accept our apologies for the error in the explanation, as this work is part of a doctoral thesis. The data analysis section has been rewritten, and it now states:

"To calculate the effect size of the main effects, partial eta squared (ηp²) was used, with values ranging from 0.04 to 0.24 considered small effects, 0.25 to 0.63 as medium, and ≥ 0.64 as large effects (Pek et al., 2018). The significance level was set at p < .05."

The reference is as follows: Pek, J., & Flora, D. B. (2018). Reporting effect sizes in original psychological research: A discussion and tutorial. Psychological Methods, 23(2), 208–225. https://doi.org/10.1037/met0000126. 


RESULTS
Comment 1: Provide main effect results first

Response 1: Thank you for the observation, as it allows for a better understanding of the impact of the observed differences. Accordingly, both the results section and Table 5 have been revised to clarify the main effects.

DISCUSSION:

Comment 1: 
This section compared the results of the present study to that of previous research, but without any speculation regarding differences or similarities in results. Please provide some context for why you think your results turned out they way they did. Some of this can be found in the Conclusion section, but there's more discussion needed to explain why the results turned out this way.

Response 1: 
Thank you for your contribution, as it ultimately aims to better frame the confirmation or rejection of potential hypotheses. In this regard, the main reason lies in the increased intensity across age categories and the consistent pattern observed with the gender factor, which is characteristic of puberty. These features have been described in general terms across different sections in order to avoid overloading the explanation for each individual variable.

 

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is a descriptive study, examining gameplay during semifinal and final tennis matches during two youth tennis tournaments. The study describes and discusses differences in variables such as match length, sets/match, strokes/point, etc., between two age groups (U-12 and U-14) and between the sexes (Males and Females). I would like to thank the authors for their work on this paper. This data would be useful for coaches and trainers of youth tennis players and would be a valuable addition to the literature. However, there are some concerns with the methodology of the study.

Abstract: Some data may be useful in the abstract.

Introduction: Overall, the introduction is well organized, and relevant studies are covered. However, the introduction at times reads too much like a comprehensive literature review instead of an introduction to the topic. This becomes apparent when comparing the amount of information and detail in the introduction and the lack of information and detail in the methods.

Line 53: Define ITF. This acronym has not been used so far in the paper.

Materials and Methods: This section has some very basic information but needs a lot of work. The sample is barely explained, and no justification for the sample size is provided. In addition, a detailed description of the data collection and data analysis methods are needed. 

Line 132: Are there any known reliability or validity metrics for notational analysis? How much training is needed to do notational analysis correctly? How many of the researchers participated in the notational analysis of each match? Is there a citation for using notational analysis?

Line 142: Was any power calculation done to determine a sample size?

Line 142: There is no demographic data about the sample or group. Average age, height, weight, nationality, time spent playing tennis, etc. How many males and females were in each group? How many individuals were in each age group?

Line 142: Are the 35 individuals equally distributed across the two categories and genders? This means about 8 people in each group. Is this enough to detect differences? Did the 35 participants play in the same number of matches? If so, what was the distribution of players in observed matches?

Line 140: What does “expert judgment” mean for participant selection? How was potential bias reduced in the participant selection?

Line 141-142: Why were only right-handed players selected? Is there a reason? Would left-handed players be expected to have different match times, strokes per point, % active time, etc.?

Line 153: How were the data collected?

Lines 155-156: Some description of the process would be useful for readers instead of just a citation. The authors spent a lot of time in the introduction introducing the problem but give almost no information about how data were collected and analyzed.

Line 158: Why was a bivariate correlation used instead of an Intraclass Correlation Coefficient? See Koo and Yi, 2016 (https://pmc.ncbi.nlm.nih.gov/articles/PMC4913118/). What interpretation framework was used to interpret correlations?

Line 157: Did the same person rate every match from each participant? If not, inter-rater reliability should be presented as well.

Line 158-168: It is stated that Cohen’s kappa and Bivariate Correlation tests are reported in table 3, but only one variable is presented. In addition, why are some scores reported at 3 decimal places, but others are only reported to 2 decimal places?

Line 171-172: What variables were tested that were below n=30 and above n=30? Why were certain participants missing from some data analyses? Why was this cutoff for performing a K-S or W-S test used? Is there a citation for this? Were all of the variables found to be normally distributed?  If they weren’t, were any other data or statistical analyses used?

Line 172-173: What variables were examined using the independent t-tests?

Line 174: Which variables were normally distributed?

Line 176-177: The independent t-test also has an assumption of homogeneity of variance. What would happen if this was violated as well?  

Line 179: What post-hoc analysis was used if the Kruskal-Wallis test was significant? As far as I am aware, the K-W test does not show simple main effects.

Lines 181-182: What effect sizes were used for which tests? How were effect sizes interpreted?

Results:

Lines 188-189: Is there a unit for hitting frequency? What was the p-value for the difference between the male players?

Lines 184-189: No reference to where data can be seen.

Lines 184-195: Were there no observed sex differences? 

Discussion: The discussion of the results was adequate and compared the results to previous research in the area. A major area of concern is an almost complete lack of a limitations section. Outside of mentioning the small sample of matches (24) and the indoor, hard-court setting, there are no other limitations mentioned. Are there no limitations inherent in notational analysis? If multiple raters were used, a concern about inter-rater reliability would be present since this was not analyzed by the researchers.

References:

Reference 1 is missing

Reference 15 is incomplete

Author Response

Before I begin responding to each of your comments in the review, I would like to thank you for your attention and dedication in helping me improve the development of the article. 

ABSTRACT
Comment 1: Some data may be useful in the abstract.

Response 2: Thank you for the comment, as it helps to improve the understanding of the scope of the results in the abstract. Although the word count is highly limited, I have managed to include those variables for which we obtained significant differences. 

 

INTRODUCTION
Comment 1: 
Overall, the introduction is well organized, and relevant studies are covered. However, the introduction at times reads too much like a comprehensive literature review instead of an introduction to the topic. This becomes apparent when comparing the amount of information and detail in the introduction and the lack of information and detail in the methods.

Response 1: 
Thank you for the observation. In this regard, we have refined the final part of the section to clarify the purpose of the research and the justification that led us to undertake it. Additionally, we have provided greater detail and depth in the methodology.

Comment 2: 
Line 53: Define ITF. This acronym has not been used so far in the paper.

Response 2: 
Thank you for the observation; the changes have already been made at line 52. 


MATERIAL AND METHODS
Comment 1: This section has some very basic information but needs a lot of work. The sample is barely explained, and no justification for the sample size is provided. In addition, a detailed description of the data collection and data analysis methods are needed. 

Response 1: 

Thank you for your contribution, as it will help improve this section of the article. In this regard, we have expanded the overall content and, more specifically, detailed the participant sample and the amount of data collected for each variable, as presented in Table 2.

Regarding the sample size, since this study involves a high-performance population, a conventional sampling approach was not followed. The number of players eligible to participate in these final phases is very limited, as this is a unique and prestigious annual tournament within the high-level competition calendar.

Comment 2: 
Line 132: Are there any known reliability or validity metrics for notational analysis? How much training is needed to do notational analysis correctly? How many of the researchers participated in the notational analysis of each match? Is there a citation for using notational analysis?

Response 2: 

I appreciate the comment, as it reflects a depth of analysis that is truly valuable.

In this case, I would like to clarify that reliability was measured using the Kappa index for nominal variables, and the correlation coefficient for quantitative variables. A reference supporting this is: O’Donoghue, P. (2009). Research Methods for Sports Performance Analysis. Routledge.

Regarding the training of the observer, it is important to note that it depends on the type of variables being analyzed. The greater the number of categories in nominal variables, the higher the level of difficulty. For temporal variables, it is crucial to precisely determine when a point begins and ends, as well as to use software that allows for frame-by-frame video analysis—both of which have been ensured in the methodology of this study, despite involving a single researcher.

Several references support the benefits of notational analysis in providing data that can help adapt training to competition demands, as well as the reliability and objectivity of such data. In this regard, the following references have been cited, among others from the fields of observational methodology and video analysis, and have been included in the introduction:

• O’Donoghue, P. (2009). Research Methods for Sports Performance Analysis. Routledge.

• Hughes, M. (2003). Notational analysis. In Science and Soccer (pp. 253–272). Routledge."
  
  

Comment 3: 
Line 142: Was any power calculation done to determine a sample size?

Response 3: 

We did not use G*Power for this study. Because it was a convenience sampling taking all the available recordings that were available. This was because it is a unique tournament that is played annually and only that sample of semi-final and final matches typical of elite players is available.

Comment 4:
Line 142: There is no demographic data about the sample or group. Average age, height, weight, nationality, time spent playing tennis, etc. How many males and females were in each group? How many individuals were in each age group?

Response 4: 
Thank you for the comment because it allows for greater clarification of the sample, only the age belonging to each group could be classified in Table 2. Regarding the rest of the demographic variables, it is worth mentioning that their access was not possible since the analyzes were carried out from videos recorded by the organization. It is an approach that we will take into account for future research.

Comment 5: 
Are the 35 individuals equally distributed across the two categories and genders? This means about 8 people in each group. Is this enough to detect differences? Did the 35 participants play in the same number of matches? If so, what was the distribution of players in observed matches?

Response 5: 
In line with the previous response, Table 2 presents the breakdown of matches, and the distinction between finals and semifinals is determined by the fact that only six matches were available for each group, as this involved data collected over several years. Nevertheless, as can be seen, the remaining variables show a large sample size, which allows for a broad representation.

Comment 6: 
Line 140: What does “expert judgment” mean for participant selection? How was potential bias reduced in the participant selection?

Response 6: 
The expert judgment in this specific context aims to support the inquiry conducted to obtain clear insights regarding performance indicators within the game structure, as well as to establish the specific guidelines for their recording. These aspects were key to ensuring intra-observer reliability, particularly in marking the beginning and end of each rally.

Comment 7: Line 141-142: Why were only right-handed players selected? Is there a reason? Would left-handed players be expected to have different match times, strokes per point, % active time, etc.?

Response 7:
Thank you for the observation, as I believe it was an aspect that was not relevant to the variables analyzed. We chose to remove it since it could lead to confusion or introduce bias that does not apply. The players analyzed were right-handed simply because they were the ones who reached these competitive rounds for which we had recorded footage available for analysis. 

Comment 8: 
Line 153: How were the data collected?

Response 8: 
In the new version, line 168 specifies that the entire match sample was obtained through recordings provided by the organization. All variables were extracted through video analysis using software that allowed for a precision of 0.04 frames.

Comment 9: 
Lines 155-156: Some description of the process would be useful for readers instead of just a citation. The authors spent a lot of time in the introduction introducing the problem but give almost no information about how data were collected and analyzed.

Response 9: 
Thank you for the observation, as it helps to better illustrate how the entire research process was carried out. In this regard, everything is referenced between lines 168 and 184. 

Comment 10:
Line 158: Why was a bivariate correlation used instead of an Intraclass Correlation Coefficient? See Koo and Yi, 2016 (https://pmc.ncbi.nlm.nih.gov/articles/PMC4913118/). What interpretation framework was used to interpret correlations?

Response 10: 
Thank you for the observation. In this regard, the type of test applied depended on the nature of the variable. All of this is presented starting from line 182. 

Comment 11: 
Line 157: Did the same person rate every match from each participant? If not, inter-rater reliability should be presented as well.

Response 11: 
Yes, the entire investigation fell on the same person. In this sense, the results of intra-observer reliability are shown in Table 4.

Comment 12: 
Line 158-168: It is stated that Cohen’s kappa and Bivariate Correlation tests are reported in table 3, but only one variable is presented. In addition, why are some scores reported at 3 decimal places, but others are only reported to 2 decimal places?

Response 12: 
Yes, I'm sorry for the error, since we use Cohen's Kappa on categorical variables. In this sense, it is an error, since a bivariate correlation was carried out in the variables of this study.

Comment 13: 
Line 171-172: What variables were tested that were below n=30 and above n=30? Why were certain participants missing from some data analyses? Why was this cutoff for performing a K-S or W-S test used? Is there a citation for this? Were all of the variables found to be normally distributed?  If they weren’t, were any other data or statistical analyses used?

Response 13: 
Thank you for this clarification. All of this has been expanded and detailed between lines 194 and 198. Likewise, the sample size can be found in Table 2, which allows for identifying which variables could be analyzed based on the distribution of the data according to their sample values.

Comment 14: 
Line 172-173: What variables were examined using the independent t-tests?

Response: 
Thank you for the observation; it allows for a better understanding of the statistical analysis. For this reason, the data analysis section has been rewritten, and the specific tests used for the analysis of each variable are now indicated. 

Comment 15: 
Line 174: Which variables were normally distributed?

Response 15: 
In the newly revised version of the data analysis section, it can be seen that ANOVA tests were conducted for those variables that met the assumptions of normal distribution and homogeneity of variances. For those that did not meet these assumptions, Mann-Whitney U and Kruskal-Wallis tests were applied. Additionally, the databases will be attached to facilitate the reproducibility of the analysis conducted.
https://drive.google.com/drive/folders/1UG44TpMlIGzlHq-6UBFAHvBmP_SLgCT1?usp=drive_link 

Comment 16: 
Line 176-177: The independent t-test also has an assumption of homogeneity of variance. What would happen if this was violated as well?  

Response 16: 
In the event that the assumption of homogeneity of variances had not been met, we would have followed specialized statistical analysis protocols as outlined in the referenced bibliography

Comment 17: 
Line 179: What post-hoc analysis was used if the Kruskal-Wallis test was significant? As far as I am aware, the K-W test does not show simple main effects.

Response 17: 
Thank you for the question, as it allows for a clearer presentation of the relevant section. In this regard, the revised version of the data analysis section now specifies the variables for which Kruskal-Wallis tests were conducted. Additionally, we have indicated that subsequent pairwise comparisons were carried out using Mann-Whitney U tests, with significance levels adjusted using the Bonferroni correction (p / number of groups). The main effects have been presented in both the updated results table 5 and the revised text. 

Comment 18:  
Lines 181-182: What effect sizes were used for which tests? How were effect sizes interpreted?

Response 18: 
Thank you for the question, as it allows me to better support the content presented in the revised version. Accordingly, partial eta squared was used as the effect size measure for the ANOVA tests. The corresponding values have been added, with values from 0.04 to 0.24 considered small effects, 0.25 to 0.63 medium effects, and ≥ 0.64 large effects (Pek et al., 2018). This information has been incorporated into the manuscript at 206 line. 

RESULTS
Comment 1: 
Lines 188-189: Is there a unit for hitting frequency? What was the p-value for the difference between the male players?

Response 1: 

Thank you for the comment, as this is a somewhat peculiar variable, yet highly relevant to the dynamics of play. In this regard, stroke frequency was measured using two variables. First, the number of strokes per point—this variable is more subjective and more difficult to compare with other studies, as it has been shown that the number of strokes per point depends on the duration of the point. For this reason, we also calculated a second variable: the number of strokes per minute, which allows for better comparison with other studies. When comparing the number of strokes per point between U12 and U14 boys, the significance level was p < .001. For the variable strokes per minute, comparisons were not made between U12 and U14 boys, as the interaction between age category and gender had no significant effect on stroke frequency per minute (F = 0.381; p = 0.544). 

Comment 2: 
Lines 184-189: No reference to where data can be seen.

Response 2: 
Thank you for the clarification. The reference to Table 5 has now been included.

Comment 3: 
Lines 184-195: Were there no observed sex differences? 

Response3: 
The datasets have been attached to allow for the replication of the results.

DISCUSSION
Comment 1: 
Thank you for the comment, as it refers to a section that we have expanded and which can now be consulted starting from line 329. Additionally, I would like to highlight that the research was carried out by a single observer; therefore, there were no concerns regarding inter-observer reliability

RESULTS: 
Comment 1: 
Reference 1 is missing

Response 1: 
Sorry for the typo, it's already resolved.

Comment 2: 
Reference 15 is incomplete.

Response 2: 
Sorry for the typo, it's already resolved.

Reviewer 3 Report

Comments and Suggestions for Authors

Following a thorough evaluation of the manuscript, several critical issues have been identified that compromise its adherence to the journal’s editorial standards. The manuscript requires significant revisions to align with the required formatting and structural guidelines.

The article does not fully comply with the journal's style, particularly regarding the title, citation format, and overall structure. The introduction is overly fragmented due to an excessive number of paragraphs and blank spaces, which disrupt the logical flow. Additionally, the citation numbering within the text does not conform to the expected formatting conventions and should be revised accordingly.

The methodology section lacks the necessary depth and organization. A more structured approach is recommended, with clear subsections dedicated to study design, procedural details, and statistical analyses. The insufficient segmentation of this section makes it difficult for the reader to fully grasp the methodological rigor of the study.

The connection between the research problem and the study objectives requires further clarification. The rationale underlying the study must be articulated more explicitly to ensure coherence between the research question and the chosen methodology.

The discussion section should provide a more comprehensive analysis, including a critical reflection on the study’s limitations, potential future developments, and practical applications of the findings. Without these elements, the discussion lacks depth and does not sufficiently contextualize the results within the broader scientific landscape.

The conclusions, in their current form, are overly detailed and should be more concise, focusing on the most significant findings and their implications. A more succinct presentation would enhance readability and reinforce the study’s key contributions.

Further concerns include inconsistencies in terminology, redundancy in certain sections, and potential misalignment of tables and figures with the journal’s formatting requirements. The overall writing style would benefit from improved clarity and conciseness to enhance the manuscript’s readability and impact.

Given the extent of the necessary revisions, it is recommended that the manuscript be rejected in its current form. However, the authors may consider a comprehensive revision addressing these critical issues for potential resubmission.

 

Author Response

Before I begin responding to each of your comments in the review, I would like to thank you for your attention and dedication in helping me improve the development of the article.

Comment 1: 
The article does not fully comply with the journal's style, particularly regarding the title, citation format, and overall structure. The introduction is overly fragmented due to an excessive number of paragraphs and blank spaces, which disrupt the logical flow. Additionally, the citation numbering within the text does not conform to the expected formatting conventions and should be revised accordingly.


Response 1: 
"Thank you for this comment, as it allowed me to carefully review the formatting details required by the journal. In this regard, the title has been revised following the capitalization guidelines, and we also took the opportunity to modify one term in order to enhance clarity from the very beginning. Regarding the references, they have been thoroughly reviewed and the previous errors have now been corrected. Finally, I would like to highlight that the white spaces have been carefully adjusted to the journal’s formatting requirements. The issue detected was due to an error in the application of line spacing settings. Regarding the issue of excessive fragmentation in the introduction, it is worth noting that its structure follows the common trend found in articles that analyze game-related variables in sports

Comment 2: 
The methodology section lacks the necessary depth and organization. A more structured approach is recommended, with clear subsections dedicated to study design, procedural details, and statistical analyses. The insufficient segmentation of this section makes it difficult for the reader to fully grasp the methodological rigor of the study. 

Response 2: 
Thank you for this observation, as it allowed us to expand the section and highlight the importance of its content. In this regard, we have provided greater depth and paid closer attention to the study design, procedural details, and statistical analysis. All of these aspects have been revised and updated within the corresponding section.

Comment 3: 
The connection between the research problem and the study objectives requires further clarification. The rationale underlying the study must be articulated more explicitly to ensure coherence between the research question and the chosen methodology.

Response 3: 
Thank you once again for this observation, which fundamentally highlights an important aspect of the research. For this reason, we have referred to the research problem and its justification in several sections of the manuscript, particularly at the end of the introduction (starting at line 119) and in the first part of the methodology section (line 128). 

Comment 4: 

The discussion section should provide a more comprehensive analysis, including a critical reflection on the study’s limitations, potential future developments, and practical applications of the findings. Without these elements, the discussion lacks depth and does not sufficiently contextualize the results within the broader scientific landscape.

Response 4: 
"Thank you once again for this contribution, as it addresses essential components of a publication of this nature. Accordingly, starting from line 329, we have included specific sections to address the study’s limitations, potential future developments, and the practical applications of the findings.

Comment 5: 
The conclusions, in their current form, are overly detailed and should be more concise, focusing on the most significant findings and their implications. A more succinct presentation would enhance readability and reinforce the study’s key contributions.

Response 5: 
Thanks to your contribution, we have been able to restructure the conclusions starting from line 355, making them more compact and concise in order to emphasize clear findings and their direct implications.

Comment 6: 
Further concerns include inconsistencies in terminology, redundancy in certain sections, and potential misalignment of tables and figures with the journal’s formatting requirements. The overall writing style would benefit from improved clarity and conciseness to enhance the manuscript’s readability and impact.

Response 6: 
We appreciate this comment, as it helped improve the preparation of the tables and once again highlighted the importance of adhering to the journal’s formatting guidelines. Efforts have been made to address terminological inconsistencies and correct the specific errors that were identified. 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

no further requests

The authors adequately responded to my comments

Author Response

Thank you very much for the attention given to my manuscript. It has been a pleasure to address your previous comments in an effort to improve its presentation.

Reviewer 2 Report

Comments and Suggestions for Authors

I would like to thank the authors for their work on the updated manuscript, which has improved from the first round. This is an interesting observation of match performance in these tournaments. However, there are still a couple of methodological concerns that might affect the interpretation of the results.

MATERIAL AND METHODS:

Lines 128-136: I understand that with this type of situation, there are limited participants. But, from your introduction, it does not appear that there are sex differences at or below U-18, or if differences are present they are minimal at best (e.g., match duration: 5.2 min, set duration: 0.4 min, game duration: 5.2 seconds, there were similar between sex findings for point duration, active time percentage, sets/match, and strokes/point, all of these are taken from the introduction). Given this, it seems odd to do a sex comparison, so some sort of justification of sample size would be useful to show that if there are differences, this isn’t due to low power levels.

Since there are a couple of sex differences found in your study (U-12: point duration and points/game), are you confident that this is not due to a Type I error? My comment below on effect sizes might be useful here as well.

Lines 138-142: Given that the matches were analyzed by a "panel", was any sort of inter-rater reliability performed? Did everyone on the panel score all of the matches? If different raters scored each match, how were inter-rater differences accounted for? This would be necessary to determine if age group or sex differences are due to differences in scoring between raters.

Lines 183-184: What standards were used to determine how Pearson’s r values were interpreted to estimate “reliability”? I know all of the values were quite high, but reporting and citing the interpretation framework is useful.

Lines 198-203: Were effect sizes calculated for these differences? Since the sample sizes are small, this would be useful information.

Results:

Table 2:

Point duration: There is a reported significant difference between U-12 males and females, but this difference is only 0.72 seconds. This begs the question of whether this result is “meaningful”. Given the small sample size could this be an error?

Strokes per point: There is a reported significant difference between U12 males and females, but this difference is 0.61 strokes. Again, is this a meaningful difference? Would half a stroke per point cause a meaningful difference in overall performance?

Again, I would like to thank the authors for their work on the manuscript. It is an interesting article, but there are some small methodological and statistical questions that need to be addressed so that the results can be put into context.

Author Response

Before addressing the comments provided, we would like to thank the reviewer for the effort invested in both rounds of review, as we believe the feedback has been constructive and has helped improve the manuscript in all the aspects highlighted.

MATERIAL AND METHODS:

Comment 1: 

Lines 128-136: I understand that with this type of situation, there are limited participants. But, from your introduction, it does not appear that there are sex differences at or below U-18, or if differences are present they are minimal at best (e.g., match duration: 5.2 min, set duration: 0.4 min, game duration: 5.2 seconds, there were similar between sex findings for point duration, active time percentage, sets/match, and strokes/point, all of these are taken from the introduction). Given this, it seems odd to do a sex comparison, so some sort of justification of sample size would be useful to show that if there are differences, this isn’t due to low power levels.

Response 1: 

Thank you very much for your contribution. A paragraph has been added indicating that the statistical power of the sample was calculated using G*Power. For a t-test with two sex groups (male and female) or two category groups (U-12 and U-14), with an effect size of d = 0.8 and a statistical power of 0.8, the required sample size is 42 matches, and our study recorded 35. Similarly, with an effect size of d = 0.7 and a statistical power of 0.8, the required sample size is 52 sets, and our study recorded 57 matches. With an effect size of d = 0.25 and a statistical power of 0.9, the required sample size is 550 games, and our study recorded 537 games. Finally, with an effect size of d = 0.1 and a statistical power of 0.9, the required sample size is 3,428 points, and our study recorded 3,527 points.

Comment 2: 

Since there are a couple of sex differences found in your study (U-12: point duration and points/game), are you confident that this is not due to a Type I error? My comment below on effect sizes might be useful here as well.

Response 2: 

Thank you for your contribution. Based on the calculated statistical power of the sample, we believe that for the variables where significant differences were found, the probability of committing a Type I error was very low (e.g., if p = .037, this implies a 3.7% probability of a Type I error). From our perspective, the opposite is also true: in variables where the sample size was large (comparisons of points and games), we found significant differences, whereas in variables related to matches or sets, where the sample size was small, we believe that the lack of significant differences may be due to a Type II error (insufficient sample size given the small effect size). For this reason, we indicated the small number of matches as a limitation of the study.

Comment 3: 

Lines 138-142: Given that the matches were analyzed by a "panel", was any sort of inter-rater reliability performed? Did everyone on the panel score all of the matches? If different raters scored each match, how were inter-rater differences accounted for? This would be necessary to determine if age group or sex differences are due to differences in scoring between raters.

Response 3: 

Thank you for your contribution. Inter-observer reliability was not conducted; however, intra-observer reliability was assessed, showing highly reliable values. This is indicated in lines 188 to 192 and in Table 4. Since there were no multiple observers involved, we understand that any differences in scoring cannot be attributed to differing observer criteria.

Comment 4: 

Lines 183-184: What standards were used to determine how Pearson’s r values were interpreted to estimate “reliability”? I know all of the values were quite high, but reporting and citing the interpretation framework is useful.

Response 4: 

Thank you for your contribution. According to Martínez-Ortega et al. (2009), values above 0.9 are considered excellent. This information has been added at 192. 

Comment 5: 

Lines 198-203: Were effect sizes calculated for these differences? Since the sample sizes are small, this would be useful information.

Response 5: 

Thank you for your comment. The results are presented in accordance with the guidelines of O’Donoghue (2009), as outlined in his book: O'Donoghue, P. (2009). Research Methods for Sports Performance Analysis. Routledge.

 

RESULTS: 

Comment 1: 

Point duration: There is a reported significant difference between U-12 males and females, but this difference is only 0.72 seconds. This begs the question of whether this result is “meaningful”. Given the small sample size could this be an error?

Response 1: 

Thank you for your comment. A difference of 0.72 seconds represents an 8% variation relative to the girls’ average time (8.76 seconds). Considering the sample size of 3,500 points, it is likely that such a difference resulted in statistically significant findings.

Comment 2: 

Strokes per point: There is a reported significant difference between U12 males and females, but this difference is 0.61 strokes. Again, is this a meaningful difference? Would half a stroke per point cause a meaningful difference in overall performance?

Response 2: 

Thank you for your comment. A difference of 0.61 strokes represents approximately 10% of the girls’ average (6.14 strokes). Given the large sample size of 3,500 points, it is likely that such a difference led to statistically significant results.

 

CONCLUSIONS: 

Finally, in response to your suggestion to provide stronger support from the results in the conclusions, I have added the contribution of the variables "active time" and "stroke frequency," allowing for a more concise and comparative conclusion.

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have addressed all of my comments and suggestions satisfactorily. I therefore consider the article suitable for publication in its current form

Author Response

Thank you very much for the attention given to my manuscript. It has been a pleasure to address your previous comments in an effort to improve its presentation.