Hell, I'm 23 and have had knee surgery(jumping out the back of a Bradley) and my back gets stiff some times(UH-60 had to make a hard landing in the Sandbox) and I still go jogging every morning, and nearly maxed out my last PT test.
Running away is a good skill to have for a foot soldier.
NRA Life Member
Ladyfriend: "I need help with the leaves in the yard"
Me: "Controlled burn?"
LadyFriend: "I forgot my Boy Scout turned into an infantry officer."