Hi been on the darkside a few years now, i ride 3-4 times a week usually one long session 4h (mainly pure trials)and 2-3 small ones 1,5 hour(street+skatepark).. main problem is HARSH landings (2m drop to flat), hang up on dirtjumps ect...other than that i do some shoulder/leg/back streching 2-3 times a week about 30min per session... i have friends in the 50's still charging...:-) so no reason to stop anytime soon...The magic trick for me seems to be warming up/ light streeching before riding 5-10min.. and loads of Coffee...