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. Hamstrings The hamstrings play a crucial role in many daily activities, such as, running, jumping, walking and cycling. Strengthening your hamstring muscles help to protect your knees from injury by absorbing the stress placed on the knee. Weak hamstrings can lead to knee injury. 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 with one foot placed on the center of the Bosu and the other foot behind. Step 2 Take a natural step forward and lift your foot over top of the Bosu, not around the side. Step 3 Step back over to the starting position. Make sure you stance doesn't become too narrow and that your feet stay about hip width apart.