Exploring the impact of professional soccer substitute players on physical and technical performance.

"Declarations Ethics approval and consent to participateThe study involves Chinese Super Soccer League (CSL) matches to quantify the difference in substitutes’ performance versus completed or replaced player for which authors have mentioned—The research project did not involve human participants, human experiments, and human data. The match data are permitted to make scientific research by the Champdas Football Big Data Company and Luneng football club. Authors confirm that all methods were carried out in accordance with relevant guidelines and regulations. This study was conducted according to the ethical principles of the World Medical Association Declaration of Helsinki and approved by College of physical education and sports, Beijing Normal University. Consent to publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding This research was funded by the National Social Science Fund youth project, "Research on the optimization of resource allocation of youth football development in China", grant ID (18CTY011)."