MUSCLES ENGAGED Quadriceps The quadriceps (quads) are a group of four muscles on the front of the thigh. They allow your knee to straighten and provide stability when standing. Your quads are the most important muscle group for maintaining the ability to stand and to walk independently. Shoulders The shoulder is the most movable joint in the body. However, it is an unstable joint because of the range of motion allowed. This instability increases the likelihood of joint injury, often leading to a degenerative process in which tissues break down and no longer function well. Equipment Used Bosu The BOSU balance trainer stands for "Both Sides Utilized" and is most often used for balance training, various athletic drills and aerobic activities. Exercise Instructions Step 1 Start in front of the Bosu with you feet shoulder width apart. Step 2 Place your hands on top of the burpee and jump back into a push-up position. Make sure to keep your back flat and your core engaged. Step 3 Jump back up to the starting position and then jump up vertically and reach for the ceiling with both hands.