Your calf muscles are important not only to walking and running, but also if you are involved in any sort of sport that involves jumping. This video provides basic exercise information for calf raises. This exercise focuses on strengthening both the foot and ankle muscles. I prefer to perform this exercise without shoes, as you can focus more on the exercise in detail. You're able to place more pressure on certain parts of the foot and ankle muscles. Wearing shoes can often take pressure off the foot and support the ankle, I recommend just completing the exercise without footwear for more resistance. If you are using this as a strengthening exercise for rehab and have had a serious injury please consult your physio before exercising.