Stretches For Bad Knees: Calf Raises
Speed is your enemy on calf raises. The calf is made up of several muscles that work together each time you take a step—that's at least 5,000 reps per day for most of us. In order to improve size and strength in this area of your body, the mind-to-muscle connection is extremely important. I suggest using a 2-1-2-1 ratio: a two-second stretch, a one-second contraction up, a two-second isometric hold at the top of the range of motion, and then a two-second eccentric motion back down.