[kevinventullo]

I suspect the compulsory aspect of a job has something to do with it as well. When I injured my wrist, I simply stopped doing exercises that aggravated the pain. This is not really an option for someone whose livelihood depends on such physical activity.

[Qem]

Was going to say that. If it's done as a work, you _must_ do it every day, even when not feeling great, so you may lack adequate time to recover. I think adequate time to recover is the difference between exercise that strengthen us, and physical activity that just grinds us down.