Take up the plank position with your legs, back, and neck forming a straight line, and your leg and stomach muscles strained. Pull your feet to your hands in a jump, then jump up, straightening your arms up as well. Return to the sitting prop position, and jump back to the initial one. Repeat 12 times.
The initial position is a plank propped on your elbows. Pull your left knee to your left elbow, then return to the initial position. Repeat with your other leg. Repeat 12 times.