High intensity excercise for joint pain

I'm finding a choreographed program called Body Balance has done me the world of good; or maybe it's just the passing of time. It's a blend of yoga. tai chi and Pilates. My knees are absolutely shot and were before all this started (again) and this program has helped me increase my flexibility, balance and strength without caning my poor worn out joints. Aqua aerobics--particularly the deep water variety--helps too. I still seize up if I sit for too long or overdo anything, but I think I'm improving.