RESUMEN
OBJECTIVE: Physical activity in a social setting is said to be associated with well-being because it provides opportunities for participants to form social relationships. However, there are inconsistent findings regarding the well-being benefits of participating in physical activity with others. To address this inconclusive evidence, we draw on the social identity approach to health and well-being to examine whether (a) the frequency of physical activity participation in a social setting and (b) the degree of social identification associated with it, have different relationships with participants' well-being. METHODS: We implemented a two-phase, mixed-methods design with members of women's only fitness clubs in Japan. In Study 1, we collected survey responses about social identification, life satisfaction, and eudaimonic well-being from 1118 members. The survey data were combined with respondents' objective participation data from a membership database. In Study 2, we interviewed a sample of club members to understand how the nature of social relationships differed depending on the degree of their social identification. RESULTS: Study 1 found that social identification with a fitness club, but not the frequency of attending the club for physical activity, was positively associated with members' well-being. Study 2 revealed that members with high social identification experienced more affective relationships with other members than those with medium or low identification. CONCLUSIONS: Our research provides quantitative and qualitative evidence supporting the association between social identification and the well-being benefits of physical activity in a social setting. It confirms the predictions of the social identity approach to health and well-being, demonstrating that people enjoy well-being benefits from physical activity participation when it is internalized as a meaningful definition of self.