MUSCLES ENGAGED 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. 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 feet hip width apart and your hands to the side. Step 2 Run on the spot pulling your knees up as high as you can. Keep your head up and chest proud the entire time. Step 3 Perform the recommended number of reps or specified amount of time.