Use a strong lifting program to identify weak points then remediate. Don't be too proud to see a massage therapist, Ortho, PT, etc. I have a knee and shoulder injury that give me problems but I have a weight program in the gym that keeps me in shape and helps me work out the little kinks so I don't tweak something kiting.
No guarantees in this sport, but being good at any discipline is 99% time on the water, 1% everything else.
I started kiting when I was 30 and riding cable when I was 31. Since then I have had both shoulders scoped my knees give me trouble from time to time as well as my lower back. I spent my 20's in the gym lifting heavy weights. I'm 37 now and I predominantly ride wake-style. I can not do all the tricks the younger guys do nor can cheat like most kiters do to land the ones I can do i.e. arms fully extended behind my back forcing a pass (my arms no longer can go back that far lol).
It's the same for me at the cable park there are just some things I can't do like 7's off the kicker. Every time I start getting close to them my back and knees start hurting from going so big off the kicker.
For me personally it's all about progression. When I can not progress anymore then I'll do something else or mow the lawn on a foil.