I've been blessed with good joints... so far... knock on wood.... for a 6'4" guy. I did tear up a hip pretty good skiing in the winter of '87, it hurts all the time but is manageable and responds well to everything except jolting impact.
I pulled a Steens deer tag again, against ALL odds, and will be doing a solo backpack hunt this fall into this terrain. The pack starts at ~ 9500 ft elevation. No trail. I have some work to do before October.