So true!! Strength training is a major factor in living not just longer but with more vigor!!A book that I was attracted to a long time ago was, Growing Old Is Not For Sissies. In there, and a lot of other places, I have always noticed people over 65 - sometimes well over, doing sports activities that relatively few do.
Swimming in the ocean near San Francisco, a woman starting into mountain climbing in her 70's was interviewed at 89 or so, 70 year old male body builder that was building muscle and bone as well as 30 year olds and looked the envy of most men.
Doing tree work through life I have always enjoyed hearing peoples personal stories. One thing I have noticed is that people who keep using their bodies - putting demand on it, keep in pretty good working order right up close to the day of their death.