Can't upvote this enough. Also, you don't need to wait until old age to see that this is true. I am half your age and even though I thought I was "fit", chronic

Can't upvote this enough. Also, you don't need to wait until old age to see that this is true. I am half your age and even though I thought I was "fit", chronic pain from years of sitting jobs revealed when I got to physical therapy that I had weaknesses in multiple muscles, many of which absolutely needed to be worked directly in order to reduce the pain, and my gym and calisthenics habits weren't doing it. Our peak species health as hunter/gatherers had us doing a wide variety of strength maintaining movements that physiology and rehab medicine is only just starting to understand. It's unbelievable for example how there are guys who can squat over 250 lbs. deeply but can't do a single one legged squat even near the same depth. Glad I got my wake up call before I got too old to do much about it.