Hi!
I can only give you an answer based on my experience, you should interview more people for more complete understanding!
1) in a team, people can be more motivated - they won't give up as easily. Also, they might be competetive so they would do more exercise than they would otherwise
2) the same holds for a classroom - motivation and competition might make students learn more
3) In a work setting the same is true, but I would also add "team spirit" - playing team sports can make people cooperate better