Velodrome,

One thing about knee pain - once you injure those little ligaments, etc., they're easily re-injured unless they're completed rehabbed.

When I started working out, it was during the Jane Fonda/Jazzercise era. We wore cute (?) outfits and NO SHOES. We jumped around on concrete. Knee pain was constant.

Proper cycling, e.g., no mashing & pedaling in a circle, has really helped. I still get knee pain, but it isn't as severe (I couldn't push down the clutch on my wimpy Toyota truck 20 years ago.)

Good fit, of course, is essential.