The advantage of keeping on encouraging him to try different sports and activities is that they will help him physically for years - I see kids who weren't encouraged/facilitated when little and they have very, very little core strength or awareness of their bodies/posture. This then makes any physical activity beyond day to day things difficult and uncomfortable, which means they're less likely to enjoy it/do it, which then increases their risk of injury, etc, etc...
It's not right seeing 11 year olds slouched, heads forward, lower back arched and legs unable to hold them up properly to the extent that they are practically walking on the inside of their ankles and sitting on a school chair causes them pain. But there are so many like that. And then they panic if they get a little bit out of breath and hyperventiliate because they've come to believe that feeling your heart beating means they're about to die.
At five, he's young enough that consistent encouragement to keep trying things that challenge him physically aren't going to be as difficult as they would be at ten or thirteen. Or forty.
And apart from being out in fresh air, communicating and working as a team, perhaps winning, etc, there are other advantages - he learns that consistently working even when something is challenging/slightly uncomfortable does have rewards. In the case of sports/exercise, he gets fitter/stronger/flexible/more able. That endorphin rush - the bit that makes you feel relaxed and happy after a good session/game/whatever - is a reward. Sleeping well is a reward. Having two hours in which you do not need to think about anything else, just focus on what is important right now is a reward. Having the strength to run faster, climb trees better, stand up longer, carry a schoolbag, stay on a bike on more uneven ground, dive into the pool without a sharp stinging slap as your skin hits the water, do your laces up or be able to get your coat on without help because your joints/muscles are more flexible - all rewards.
It may be that it takes a while for him to find something he really enjoys, but even the act of trying different things is good. Maybe he'd enjoy martial arts, maybe dance, maybe something else as he gets older - but keeping on trying so that he potentially finds something that is right for him is a good thing.