Exploring coach and parent transformational leadership and their associations with social identity in adolescents.

The main objective of this study was to explore the associations between the transformational leadership of coaches and parents and adolescent athletes' social identity and examine the roles of gender and the stage of adolescence in these relationships. Furthermore, this study aimed to provide empirical evidence on measurement invariance across gender and the adolescent stage in the adapted Spanish version of the Social Identity Questionnaire for Sport (SIQS). The sample consisted of 656 athletes (299 males and 357 females) from 12 to 18 years old (M = 15.27, SD = 1.64) who participated in various team sports. All the participants completed a socio-demographic questionnaire, the Social Identity Questionnaire for Sport, and the Transformational Coaching and Transformational Parenting Questionnaires. The results confirmed the scalar measurement invariance of the adapted Spanish version of the SIQS across gender and adolescent stage. Transformational coaching and mothers' transformational parenting positively predicted adolescents' social identity across gender and adolescent stage. Additionally, during early adolescence, fathers' transformational parenting was also associated with their children's social identity. These findings emphasize the importance of transformational leadership in both team and family contexts in promoting athletes' social identity.