The social identity approach has become an important framework for understanding effective leadership. The present study is the first to longitudinally examine the relative impact of coaches' and athlete leaders' identity leadership on athletes' identification with their team, as well as the subsequent relationships with key team and individual outcomes. To investigate these research questions, 18 sport teams (N = 279) completed a questionnaire early and late in their season competition. To analyse these data, we conducted structural equation modelling and controlled both for baseline values and the nested structure of our data. Results revealed that it was mainly the identity leadership of athlete leaders (and not of the coach) early in the season that predicted athletes' team identification later in the season. This increased team identification in turn fed into both team outcomes (i.e., task climate, team resilience, team performance) and individual outcomes (i.e., well-being, burnout, and individual performance). The mediating role of team identification suggests that by building a shared sense of 'we', athlete leaders can improve the team's effectiveness and enhance athletes' well-being. Accordingly, we conclude that empowering athlete leaders and strengthening their identity leadership skills is an important way to unlock sport teams' full potential.
Keywords: Athlete leadership; peer leadership; performance; social identity; team identification.