In order to get the most out of your aerobic exercise, it is important to make sure you are jumping properly. You do not want to injure yourself or develop stress fractures. When you are jumping, you should be sure to propel yourself with your hips, knees, calves, and ankles. Push the balls of your feet down into the floor as you jump, with your toes down when you leave the ground. When you are landing back on the floor, the goal is to land softly and make only brief contact with the ground. Focus on dispersing the shock through your legs. Your heels should not even touch the ground.