As I have aged, now 71, I find the years of overuse and abuse to be my main areas of pain. I thought Seals and Rangers hand to hand combat until I was 55 and competed in full contact fighting until I was 55.
I never lost because I found in my 60's that I have two double fast-twitch muscle alles. What is that? Ever seen the film clip on Bruce Lee knocking someone into a chair with only the distance of extending his fingers, maybe 2-3 inches.

IMPORTANT point if you can do this. I had extreme lower back pain with nerve pain running down both legs when i was 30. By the grace and peace of God I found a board that bent at my hip and supported my butt and back. I used it for years to strengthen my abdominal muscles and have had over 30 years of pain-free lower back and legs. A miracle and if you can find an apparatus like that and even if you start with a few inches. I have been pain-free for years.