I have bad knees. I need a good 10 miles of spinning without using the muscles hard to feel good. If I start off too hard or fast, I end up slower and hurting. So I have learned to go out easy and warm up gently, staying in easy gears. In colder weather, I live by Icy Hot. (Its a cream like Ben Gay) It warms the knees up and feels like a nice massage. Although smelly, it works for me!