Every time I start getting back into it and getting into decent shape, my old knees start going out on me. They swell up and I can't hardly walk without limping. Back about 8 or 9 years ago, you wouldn't have recognized me. I was about 175 pounds and could spar for hours without getting tired one little bit. Then I did something to both of my knees, ligaments and tendons got BADLY strained so now I have problems when I get back at it hard. Course I was in my mid 30's back then, not mid 40's LOL