Maybe it's because I got into this line of work a bit late, but I see guys younger than me limping with bad knees or feet, aching elbows and shoulders, and I'm still waiting to see where this job doesn't make me stronger.
Feeling stronger everyday, never felt better, but I use every technique and aid I can come up with to make my work in the tree smooth, easy, and controlled.
Control is the key. Control of your body, control of your rope. Control of your saw, which in turn, controls what you cut.
There isn't anything involved in aerial tree work that should physically burn a person out. If you feel used up after a climb, you did it wrong.
Back injuries on the ground, compounded time and time again from moving wood around on the ground, end more climbers careers short than any other injury I can think of.
Knees and backs are screwed up by overextending and poor technique on the ground more often than in the tree.
My 2 sense.
RedlineIt