Quadraped -- Targets your core. Another Pinner wrote, "It's a muscle endurance workout. This was my first time doing this & I must say it was pretty hard." Flip the Bosu ball on it flat side. Start with hands & knees on a comfortable spot on the ball. When you feel balanced, lift one arm & opposite leg keeping them as straight as possible. Hold position for no longer than 40 seconds. Then repeat on the other side. 30-45 sec x 3 sets