Get into a push-up position with your hands on top of smaller medicine balls, a Bosu or stability ball (you can do this without smaller medicine balls and just rest your hands on the floor) and your toes on top of a stability ball or resting on the floor. Lower your chest until your upper arms are parallel to the ground and your body is in a straight line from head to heels. Lift your left foot off the ball so you're balancing on your hands and right toe. Hold this position for 15 seconds, and then complete 5 push-ups. Rest 30 seconds and repeat, this time lifting your right foot off the ball.
Complete 5 sets on each leg.