JUMPING JACKS

Jumping-jack pyramid Do as many jumping jacks as you can in 10 seconds. Rest for an equal amount of time. Next, do as many jumping jacks as you can in 20 seconds, and rest 20 seconds. Then do 30 seconds of jumping jacks followed by 30 seconds of rest. Now work your way back down the pyramid (30, 20, 10). Repeat three times. This will change the way you think about jumping jacks forever.