How do the pros stay fit?

Other than jamming, which I have found to be pretty demanding on this old bod, how do the pros prepare for the unique rigors of our sport?
I think it would be useful for many of us to learn about athletes’ stretching and strengthening routines, in particular.
I’m all for swelling the freestyling ranks and would like to remain in them for as long as possible.
Thanks in advance for your help!