It doesn't need to be a fight. We can generalize to competitions, where we have examples such as athletes and gymnasts (who in particular are amazing). But you can also look at performers outside pure competitions too: acrobats and dancers are also very fit individuals.

Fight and competition are too specific. There's just needs to be some well defined goal to move towards, it just so happens that competition is one of the best ways to provide that. And since competitions need not be violent, let's prefer to use that terminology instead.