The Extreme Balance Board is just that - extreme. You have to be out of balance to develop balance. With 3 different adjustable skill levels, this balance board becomes more challenging as you improve. Wooden board with rubber traction. Wooden rocker. Use the Extreme Balance Board for rehabilitation and prehabilitation - the dynamic balance and proprioception demands strengthens ligaments, joints and muscles to prevent injuries. Transfers strength over to a functional sport environment. Coach Twist’s athletes also use the balance board as a warm up to stimulate the nervous system and activate muscles prior to strength training. Stronger and safer lifts result.