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. Calves Calves (calf muscles) influence the ankles and contribute to overall ankle strength. Strengthening your calf muscles will help your balance and performing movements such as running, walking and jumping. Exercise Instructions Step 1 Start in a standing position with your arms at your side and your feet hip width apart. Step 2 Sink in to your hips and knees with control and then explode out of the hole and jump into the air. Step 3 Fully extend your hips, knees and ankles at the top of the jump and land softly back to the ground.