Hi, Thanks everybody for suggestions for non-impact. Today I felt like I got a great workout, (we will see how I feel tomorrow). I did the bike for 30 min then PH minus squats and lunges. In place of the lunges I did glute lifts on all fours with a weight behind my knee. I think this should be ok because the glute was lifting the leg not my knee. What muscles am I using most in the stationary bike? I felt it most in my quads, so should I focus on floor work for hamstrings? I can do dead lifts, they dont put stress on the knee. I dont want these legs to lose the definition PH has giving them.