Wonder if the number of marathons completed correlates with the incidence of eventual knee and hip replacements. Everyone obeys the laws of physics.
Apparently not.
Before I retired out of the military in the late 1990s...there was this decade of heavy physical fitness ‘push’ going on. I had begun to have joint and pain issues. Once I retired out...I stuck with mostly walking (no knee or hip replacement). If you go around a base today and chat with younger folks, you find that there is a little industry base of guys getting to early 30s and being considered for knee replacements.
In a way, they’ve become like major league athletes and having various issues now in their 40s. It just doesn’t make sense for this many people to be in consideration of knee/hip replacements.