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. Exercise Instructions Step 1 Start by sitting up against the wall making sure that your butt is touching the wall and your tailbone is making contact with the floor. Step 2 Open your legs until you feel a stretch in your inner thighs. Step 3 Try your best to relax in this position and hold for 2 minutes.