A couple years ago I tore my right hamstring away from the growth plate and part of my piriformis muscle. My doctor said it healed as much as it could without getting surgery, but it still causes pain often. I really want to strengthen my legs more to make them strong and toned, while also strengthening where my injuries were to hopefully prevent more damage. Many exercises I know for legs, however, like squats and lunges, start to really hurt that area after many reps like what's needed to get results. Does any one have any exercises I could try to strengthen my old injured areas and upper legs that might be less painful?