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. Back (upper) You can’t see your back without a lot of effort, but this doesn't mean you shouldn’t train it. Back exercises consisting of both back stretching and back strengthening is very important to your health and overcoming back pain. Exercise Instructions Step 1 Start in a standing position with your feet hip width apart and your hands interlocked in front of you. Step 2 Step back into a lunge position and raise your arms over your head, keeping your chest proud and your spine fully extended. Step 3 Stand back up into your starting position, lower your arms and repeat.