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. Back (lower) The lower back is often not trained because it is not visible in the mirror. If you have weak lower back muscles, there is nothing to help pull back against the spine, putting you at risk of developing poor posture (hunched over). Weak lower back muscles can also lead to lower back pain. Exercise Instructions Step 1 Start in a standing position with your feet about shoulder width apart and your hands over your head. Step 2 Bend forward at your hips and try to stretch your hamstrings as you reach towards the ground. Step 3 Walk out into a modified push-up position, drop your hips and pull your chest up and try to feel a stretch in your hip flexors.