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Article History

Accepted: 9 September 2025

First Online: 15 November 2025

Declarations

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: The results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. Edgar Schwarz receives a scholarship from the “Deutsche Fußball Liga GmbH” (DFL) that operates the German Bundesliga 1 and 2. Tim Meyer is chairman of a DFL working group entitled “Medicine in Professional Football” and chairman of UEFA’s and the German FA’s (DFB) medical committees. Rob Duffield is the Head of Research and Development at Football Australia. Julio A. Costa works as a Sport Scientist for the Portuguese Football Federation. Agustin Alanis, Marcela Alanis, Aldo Lara and Alfredo Freeze work in the Medical and Performance Unit of the Club de Fútbol Tigres de la Universidad Autónoma de Nuevo León (Club Tigres UANL). The remaining authors have no competing interests to declare.

: The datasets generated and/or analyzed during the current study are not publicly available due to being team-specific data of Club Tigres UANL but are available from the corresponding author upon reasonable request.

: Ethics approval was granted by the Ethics Committee of the Faculty for Human and Business Sciences of Saarland University (Ref No.: 23–14). At the time of application, the exact location for data collection was not yet determined, but the committee was aware that data collection might involve international settings. Although Mexican and German youth football academies work similarly (mostly affiliated to professional league clubs providing professional environments to train and develop players), further steps were taken to exclude any regional ethical concerns. The study protocols were additionally reviewed and approved by both the Club Tigres UANL and the organization of the Mexican Football League (LigaMX) ensuring consideration of local ethical factors. Therefore, this study was conducted in accordance with the Declaration of Helsinki.

: Following an explanation of study procedures and measurements during an initial familiarization session, participants provided written informed consent. All participant information and communications were held in Spanish and written informed consent was provided in Spanish to ensure the participants’ understanding of the protocols.

: Study conception and design were performed by ES, CBO, AA, JC, TM and RD. Material preparation was performed by ES, CBO, MDM, AA, MA, AL, AF, JC, TM and RD. Data collection was performed by ES, CBO, MDM, AA, MA, AL, AF and RD. The first draft of the manuscript was written by ES, TM and RD, and CBO, AA and JC later commented on previous versions of the manuscript. All authors read and approved the final manuscript.

: This study was registered at the German Clinical Trials Register with the DRKS-ID: DRKS00032208, which can be accessed at: .