Many people believe in order to strengthen their legs they need to join a gym or purchase expensive leg weight machines. In fact, one can strengthen and tone their legs using the force of gravity. Leg lifts are a body weight exercise that uses your own legs as weight. Simply lie on the ground with your legs extended straight in front of you. Keeping your knees locked,  lift our heels about six inches off the ground. You then hold this position as long as you can. If you don’t feel the burn from this bodyweight exercise, you are not doing it correctly. It works the legs and the stomach muscles better than anything you can do at the gym or with expensive equipment.