I am 37, and here are my thoughts. Respect your recovery time first and foremost. When I was in my twenties I could go 12-15 rounds of heavy sparring (kick-boxing) and do it all over again first thing in the morning the next day, now it takes 2-3 days before I can do that intensity again. I find the same applies to Jiu-Jitsu. If your body needs a recovery time take it, don't avoid practice just focus on technique and skill when you are there. I have focused a lot on posture and body balance when lifting weights or exercising. Also, in my goal to walk on my hands I have begun researching and adding gymnastics programming elements to my work-outs, which seems to have a lot of Yoga type movements as well. The other thing I do and have done for a while now is 'no-hands' treading water (hands clasped on head, egg-beater(slow set) or flutter-kick(fast set)) for the lengths of rounds and duration of fights, rest time is the only time you can use hands to scull. If that gets too easy, add a diving weight belt. As well, after the last Portland seminar Geo has motivated me to find some scrap linoleum, get out my sony blaster and do some coffee-grinders and windmills 1984 style.