The Effect of the Number of Substitutions on Running Activity in Professional Football Matches: An Observational Study from the Swiss Super League

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors, the work sent to me for review requires several additions and corrections within individual sections.

Material and methods:

in this section, please add a graph illustrating the course of the research process, taking into account the selection, number of subjects, and criteria for inclusion and exclusion from the study
- please indicate what method was used to select the research material

results:
please emphasize the statistical significance of the obtained results in the tables
-in addition, please present the key results in the form of graphs
- was an analysis carried out showing how the number of changes affects the tested parameters in relation to the sports level of the competitors? (were any parameters about the level of efficiency and effort capabilities of the competitors tested and determined), especially those who were substitutes? This could be an interesting analysis enriching the results

discussion:
in the discussion it is worth adding information and referring to the fact that usually reserve players are at a slightly lower loss level than the main players and this may be the reason for achieving worse results in terms of the parameters tested. It is the coach who decides in accordance with his knowledge, experience and the results of the observations and tests which players play in the main line-up and which are substitutes. It is also worth adding about the factor of motivation to make an effort and it may be important for substitutes to show themselves from the best side, which may have an impact on the values ​​of the results obtained

best regards

Author Response

I would like to sincerely thank the reviewers for their thoughtful and constructive comments on our manuscript. We highly appreciate the time and effort they dedicated to reviewing the article. In response to the reviewers' suggestions, we have made several revisions to the manuscript. All changes have been clearly marked in red text for easy identification. We believe these modifications have strengthened the overall quality of the manuscript and addressed the points raised by the reviewers.

 

• Reviewer 1

Dear Authors, the work sent to me for review requires several additions and corrections within individual sections.

 

Comment:

Material and methods: in this section, please add a graph illustrating the course of the research process, taking into account the selection, number of subjects, and criteria for inclusion and exclusion from the study.

- please indicate what method was used to select the research material

 

Answer: Comment acknowledges. In our case, an observational design was used to examine a professional football team. The subjects are 32 professional soccer players that were analysed during 43 matches. All this information is specified in the methods section. The only exclusion criteria are few and clear: no goalkeepers; matches in which a player was sent off or the team did not finish with 11 players and matches that presented goal differences greater than two goals. As we have several tables and figures, I think it is not necessary to expand as this information is clearly defined. If, on the other hand, you consider it relevant, of course we will do it. Please let us know and thanks.

 

Comment:

results:

please emphasize the statistical significance of the obtained results in the tables

Answer: Thank you for this clarification. We have highlighted the significant values in the tables.

 

Comment:

-in addition, please present the key results in the form of graphs

Answer: Thank you for this valuable suggestion. We have added figures with ES to make the results clearer, highlighting the statistically significant values.

 

Comment:

- was an analysis carried out showing how the number of changes affects the tested parameters in relation to the sports level of the competitors? (were any parameters about the level of efficiency and effort capabilities of the competitors tested and determined), especially those who were substitutes? This could be an interesting analysis enriching the results

Answer: Thank you very much for this comment. Unfortunately, this aspect was not studied in this work. As the reviewer rightly suggests, it is an interesting aspect that should be addressed, so we will take it into consideration for future research. Thanks.

 

Comment:

discussion:

in the discussion it is worth adding information and referring to the fact that usually reserve players are at a slightly lower loss level than the main players and this may be the reason for achieving worse results in terms of the parameters testedIt is the coach who decides in accordance with his knowledge, experience and the results of the observations and tests which players play in the main line-up and which are substitutes. It is also worth adding about the factor of motivation to make an effort and it may be important for substitutes to show themselves from the best side, which may have an impact on the values ​​of the results obtained.

Answer: Thank you also for this point of reflection. Regarding the first aspect, some studies suggest that substitute players may cover greater distances compared to a full second half; however, they do not necessarily reach the running demands they would typically achieve during the first half if they had started the match (P. S. Bradley et al., 2014; Carling et al., 2010; Hills et al., 2018; Mohr et al., 2003). On the other hand, the coach's decisions and motivation represent an interesting perspective to gain a more comprehensive view of the situation, even though they remain subjective parameters that are not always easily standardized. We appreciate this valuable perspective and will include a reference to it in our discussion.

 

• Bradley, P. S., Lago-Peñas, C., & Rey, E. (2014). Evaluation of the Match Performances of Substitution Players in Elite Soccer. International Journal of Sports Physiology and Performance, 9(3), 415–424. https://doi.org/10.1123/ijspp.2013-0304
• Carling, C., Espié, V., Le Gall, F., Bloomfield, J., & Jullien, H. (2010). Work-rate of substitutes in elite soccer: A preliminary study. Journal of Science and Medicine in Sport, 13(2), 253–255. https://doi.org/10.1016/j.jsams.2009.02.012
• Hills, S. P., Barwood, M. J., Radcliffe, J. N., Cooke, C. B., Kilduff, L. P., Cook, C. J., & Russell, M. (2018). Profiling the Responses of Soccer Substitutes: A Review of Current Literature. Sports Medicine, 48(10), 2255–2269. https://doi.org/10.1007/s40279-018-0962-9
• Mohr, M., Krustrup, P., & Bangsbo, J. (2003). Match performance of high-standard soccer players with special reference to development of fatigue. Journal of Sports Sciences, 21(7), 519–528.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

I first want to thank the authors for their submission and applaued them for this very practical application analysis. I have a couple of comments that I would like to see answered before recommending publication of this manuscript.

 

The first comment I have is that when reading the introduction it appears that the authors believe that differences would be seen between the two groups. However, the discussion points to the findings supporting previous investigations in relation to the variables of this study. I would highly encourage the authors to discuss the null hypothesis point of view that is presented in the discussion in the introduction. This would also aid in the justification of the study more based on the new substitution rules.

 

I have a concern about the independent sample t test that was used between the two groups as individual players were in both groups. Why would you not use the paired samples test that was used in the between halves analysis? Adding to the exclusion criteria that individuals had to appear in both groups. 

In the statistical analysis there is no mention of the 2nd half only analysis that is reported in table 3.

Why did you use the specific sprint velocity windows?

Did all players reach the >25.2kph window? If not, this should be reported and discussed.

What was the impact of the rule change on the average minutes played by subs and GPS data? I feel as if this would be a very strong addition to the current manuscript.

 

 

 

Author Response

I would like to sincerely thank the reviewers for their thoughtful and constructive comments on our manuscript. We highly appreciate the time and effort they dedicated to reviewing the article. In response to the reviewers' suggestions, we have made several revisions to the manuscript. All changes have been clearly marked in red text for easy identification. We believe these modifications have strengthened the overall quality of the manuscript and addressed the points raised by the reviewers.

 

• Reviewer 2

 

Comment:

The first comment I have is that when reading the introduction it appears that the authors believe that differences would be seen between the two groups. However, the discussion points to the findings supporting previous investigations in relation to the variables of this study. I would highly encourage the authors to discuss the null hypothesis point of view that is presented in the discussion in the introduction. This would also aid in the justification of the study more based on the new substitution rules.

Answer: Thank you very much for your comment. We agree with your suggestion and have placed greater emphasis on the null hypothesis perspective in the introduction.

 

Comment:

I have a concern about the independent sample t test that was used between the two groups as individual players were in both groups. Why would you not use the paired samples test that was used in the between halves analysis? Adding to the exclusion criteria that individuals had to appear in both groups.

 

Answer: Comment acknowledges. When we compare the first and second part, we compare the same individuals in both situations (1 vs 2 half). However, when we compare group A (players involved in matches with ≤ 3 substitutions) vs. group B (players involved in matches with > 3 substitutions), in this case it is not the same individuals involved in both situations. However, if the reviewer wants, we can change the statistics to paired samples test.

 

Comment:

In the statistical analysis there is no mention of the 2nd half only analysis that is reported in table 3.

Answer: We greatly appreciate this comment. In accordance with the reviewer’s suggestion, the statistical analysis section has been revised to include the analysis of the second half.

 

Comment:

Why did you use the specific sprint velocity windows?

Answer:  Thank you very much for this comment. The authors used these velocity windows following the thresholds that have been previously used in similar articles published in the scientific literature.

 

• Kobal, R.; Aquino, R.; Carvalho, L.; Serra, A.; Sander, R.; Gomes, N.; Concon, V.; Ramos, G.P.; Barroso, R. Does the Number of Substitutions Used during the Matches Affect the Recovery Status and the Physical and Technical Performance of Elite Women’s Soc-cer? Int. J. Environ. Res. Public. Health 2022, 19, 11541, doi:10.3390/ijerph191811541.
• Di Salvo, V.; G., W.;. Atkinson, G.;. Tordoff, P.;. Drust, B. Analysis of High Intensity Activity in Premier League Soccer. Int. J. Sports Med. 2009, 30, 205–212, doi:10.1055/s-0028-1105950.
• Rampinini, E.; Coutts, A.; Castagna, C.; Sassi, R.; Impellizzeri, F. Variation in Top Level Soccer Match Performance. Int. J. Sports Med. 2007, 28, 1018–1024, doi:10.1055/s-2007-965158.

 

Comment:

Did all players reach the >25.2kph window? If not, this should be reported and discussed.

Answer: Thank you for this valuable clarification. We will include this interesting point in the discussion section.

 

Comment:

What was the impact of the rule change on the average minutes played by subs and GPS data? I feel as if this would be a very strong addition to the current manuscript.

Answer: Thank you for your comment. We have incorporated your suggestion into the manuscript as recommended.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Introduction

The study titled “The Effect of the Number of Substitutions on Running Activity in Professional Football Matches: An Observational Study from the Swiss Super League” employs an observational research design to investigate the impact of increased substitutions on running performance in professional football. The study utilizes GPS tracking technology to assess total distance covered, sprinting distance, and acceleration/deceleration patterns. While the research provides valuable insights into substitution effects, several methodological and statistical concerns affect the robustness of its conclusions.

Strengths:

1. The study effectively leverages global navigation satellite system (GNSS) technology to measure running activity with high precision. The application of GPS ensures accurate and objective quantification of performance metrics, enhancing data reliability.
2. The study categorizes running activity metrics, such as sprint distance, total distance covered, and acceleration/deceleration rates, aligning with existing sports science literature.
3. The division of matches into two groups (≤3 substitutions vs. >3 substitutions) enables a direct comparison of substitution effects, facilitating structured analysis.

 

Weaknesses:

1. The study is based on a single team in the Swiss Super League, significantly restricting external validity. A multi-team or multi-league approach would enhance generalizability and ensure findings apply to broader football settings.
2. The study does not account for factors such as match importance, playing conditions, or opposition quality, which could influence physical exertion.
3. Tactical differences between matches with varying numbers of substitutions are not discussed, potentially affecting the interpretation of results.
4. The study does not include a power analysis to justify the sample size, raising concerns about whether the study was adequately powered to detect meaningful differences. Without a pre-determined effect size estimation, the findings may suffer from Type II errors (failing to detect a real effect).
5. The study does not account for intra-team or inter-match variability, which is known to impact running performance.
6. While p-values are reported, effect sizes are not sufficiently contextualized regarding practical relevance for coaches and practitioners. Statistical significance does not necessarily equate to meaningful changes in performance, and additional discussion on real-world implications would strengthen the conclusions.

 

I have one crucial suggestion for the authors. To enhance its rigor and validity, the authors should consider incorporating one of the following advanced statistical techniques despite the challenges posed by their computational complexity and required expertise. To enhance statistical rigor, the study could apply:

1. Mixed-Effects Models to control for variability across matches and players.
2. Generalized Estimating Equations (GEE) for handling repeated measures and within-match dependencies.
3. MANOVA to assess interrelated performance metrics comprehensively.
4. Effect Size with Confidence Intervals to enhance practical significance over p-values.

Author Response

I would like to sincerely thank the reviewers for their thoughtful and constructive comments on our manuscript. We highly appreciate the time and effort they dedicated to reviewing the article. In response to the reviewers' suggestions, we have made several revisions to the manuscript. All changes have been clearly marked in red text for easy identification. We believe these modifications have strengthened the overall quality of the manuscript and addressed the points raised by the reviewers.

 

• Reviewer 3

 

Comment:

Weaknesses:

1. The study is based on a single team in the Swiss Super League, significantly restricting external validity. A multi-team or multi-league approach would enhance generalizability and ensure findings apply to broader football settings.

Answer: Thank you for your comment, we fully agree with your observation. We have included this point among the study's limitations, and we will also incorporate your suggestion.

 

Comment:

2. The study does not account for factors such as match importance, playing conditions, or opposition quality, which could influence physical exertion.

Answer: While we agree with your point, it is also true that there are conflicting opinions on this topic. Research has shown that situational factors like match outcome, location, and team quality significantly influence performance in elite soccer (Aquino et al., 2020; Lago et al., 2010). Rampinini et al. (2007) found that the physical performance of a team, is influenced by the opponent's competitive level, with small effect sizes observed. However, no significant difference was found for very high-intensity running (Rampinini et al., 2007).

Conversely, Modric et al. (2022) found no effect of match outcome, match location, team, or opponent quality on total distance and high-intensity running. across all playing positions.

Considering these contrasting perspectives, our study focuses on a single team within the leagues, which inevitably competes against the same opponents throughout the season. This consistency reduces the risk of bias related to team quality since the analyzed team remains constant while facing the same set of opponents. Despite this we will add in the limitations of the study this aspect.

 

• Rampinini E, Coutts AJ, Castagna C, Sassi R, Impellizzeri FM. Variation in top level soccer match performance. Int J Sports Med. 2007 Dec;28(12):1018-24. doi: 10.1055/s-2007-965158. Epub 2007 May 11. PMID: 17497575
• Aquino, R.; Carling, C.; Palucci Vieira, L.; Martins, G.; Jabor, G.; Machado, J.; Puggina, E. Influence of situational variables, team formation, and playing position on match running performance and social network analysis in brazilian professional soccer players. J. Strength Cond Res. 2020, 34, 808–817
• Lago, C.; Casais, L.; Dominguez, E.; Sampaio, J. The effects of situational variables on distance covered at various speeds in elite soccer. Eur. J. Sport Sci. 2010, 10, 103–109
• Modric, T.; Versic, S.; Alexe, D.I.; Gilic, B.; Mihai, I.; Drid, P.; Radulovic, N.; Saavedra, J.M.; Menjibar, R.B. Decline in Running Performance in Highest-Level Soccer: Analysis of the UEFA Champions League Matches. Biology 2022, 11, 1441. https://doi.org/10.3390/biology11101441

 

Comment:

3. Tactical differences between matches with varying numbers of substitutions are not discussed, potentially affecting the interpretation of results.

Answer: Thank you for your valuable feedback. Your comment is valid, and we fully agree. We will include it in the study's limitations.

 

Comment:

4. The study does not include a power analysis to justify the sample size, raising concerns about whether the study was adequately powered to detect meaningful differences. Without a pre-determined effect size estimation, the findings may suffer from Type II errors (failing to detect a real effect).

Answer: Thanks to the reviewer for the recommendation. It is well documented by several articles that post hoc power calculations could not be useful (Althouse, 2020; Goodman & Berlin, 1994; Hoenig & Heisey, 2001). Based on this, and on the fact that we have tables within the results with a lot of information (effect sizes (ES±95%CI) and P value), we think that we will overload the table with more information and it will not provide substantial information in addition to the sum of ES + P value. However, if the reviewer considers that we must include it, please confirm it and we will do it. Thanks again.

 

• Althouse, A. (2021). Post hoc power: Not empowering, just misleading. Journal of Surgical Research, 259, A3--A6.
• Goodman, S. N., & Berlin, J. A. (1994). The use of predicted confidence intervals when planning experiments and the misuse of power when interpreting results. Annals of Internal Medicine, 121, 200--206.
• Hoenig, J. M., & Heisey, D. M. (2001). The abuse of power: The pervasive fallacy of power calculations for data analysis. The American Statistician, 55, 19--24.

 

Comment:

5. The study does not account for intra-team or inter-match variability, which is known to impact running performance.

Answer: Thank you for your comment. We will include it in the study's limitations.

 

Comment:

6. While p-values are reported, effect sizes are not sufficiently contextualized regarding practical relevance for coaches and practitioners. Statistical significance does not necessarily equate to meaningful changes in performance, and additional discussion on real-world implications would strengthen the conclusions.

Answer: Comment acknowledged and changes have been made in the discussion and also conclusions.

 

Comment:

I have one crucial suggestion for the authors. To enhance its rigor and validity, the authors should consider incorporating one of the following advanced statistical techniques despite the challenges posed by their computational complexity and required expertise. To enhance statistical rigor, the study could apply:

1. Mixed-Effects Models to control for variability across matches and players.
2. Generalized Estimating Equations (GEE) for handling repeated measures and within-match dependencies.
3. MANOVA to assess interrelated performance metrics comprehensively.
4. Effect Size with Confidence Intervals to enhance practical significance over p-values.

 

Answer: Thanks for your suggestions. The statistics we have used are commonly employed in this type of article published in scientific literature. We will take your consideration into account for future articles. Effect size with confidence intervals are included in the statistical analysis and new figures have been added with the ES±95%CI based on requests from another reviewer. On the other hand, if you think we should change the article's statistics completely, please let us know exactly what you want, and we will do it. Thanks again.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors Dear Authors, Thank you for taking my comments and suggestions into consideration,
I leave the decisions on publishing the work to the Editors.
best regards

Reviewer 3 Report

Comments and Suggestions for Authors

Thank you for including my comments.