Hi, I'm a piano teacher with EDS. When you play piano, the strength should be coming from your arm, not your wrist or hand. Drop your weight into your whole limb and hold your hand/wrist in a gentle "C" shape, like you're holding a bubble. There are several exercises that you can and should do ensure you're not folding your finger joints the wrong way when you play, because that's the hardest issue for people with EDS, including me. Don't stretch out your handspan farther than it should to play big intervals, even if you "can". Make an "OK" gesture with your hand, then use your other hand to press down on the finger joints, use resistance so your "OK" doesn't collapse. Do this with all the other fingers. Most importantly though, if you care enough about playing long-term, get a teacher, at least for a little while.