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 off standing on one foot with a soft bend in your knee, your back straight and your shoulders pulled back. Step 2 Keep a soft bend in your knee and your lower back flat as you bend forward and touch the floor in front of you. Step 3 Pull your body back up to a standing position and repeat.