I think we were all born to run but if we don't get started until we're in our 50's
bad posture, habit and wear and tear make it pretty tough to do.
Just compare our physiques to any of the other apes or primates. We were absolutely built to run. I'm a good example, it hurts me to run. Why start now? I like walking, cycling...
but when I was 20, i could run effortlessly. Not far, because I wasn't in shape...