Jumping Jacks are a full-body exercise that involves jumping to a position with the legs spread wide and the hands touching overhead, then returning to a position with the feet together and arms at the sides. This exercise is great for warming up as it increases heart rate and engages multiple muscle groups. To perform a Jumping Jack, start by standing upright with your feet together and arms at your sides. Jump up, spreading your legs shoulder-width apart while simultaneously raising your arms above your head. Quickly return to the starting position and repeat.