This article looks interesting, they found social support and social norms contribute independently to the frequency of strenous leisure-time exercise.

This study conducted in the US students in school of psychology, and resulted three major findings: 

1. Esteem social support and descriptive norms related to friends make independent, positive contributions to the prediction of frequency of strenuous leisure-time exercise.

2. Social norms and social exchanges should be conceptualized as multidimensional constructs.

3.  Esteem social support from friends had a large, positive effect on the frequency of strenuous leisure-time exercise. Whereas the effects of companionship social support from friends and information social support from friends were negative.

In a simple explanation, I have no doubt on the complexity of social support related to exercise behaviour. You may have seen that we often participate exercise which our friends actually do rather than they suggest.

To imply these findings, young adults in US perform physical-leisure activities influencing from friends and socialization.

What is about in Thai adolescents? I do hypothesize that friendships and family support may impact on the selection of leisure activities, rather than Thai social support or social norms. Thus, being yourself in participating physical leisure activities is the most important consideration....What do you think about this issue?