knee pain will happen. You need stretch REALLY well before you exercise. That’ll help a lot and you won’t feel the pain as much. Also, your feet have to stay firmly planted. Your heel should not bounce. The fact that your heel moves up and down means that you’re messing up the balance in the foot.

Move your legs with machine not separate.

I do the exact same thing and I’ve never had any problems with my body. I have pains from the treadmill though, but I do the same thing, I don’t think it’s bad.