Quadriceps

The quadriceps is a large muscle at the front of the thigh which helps to straighten the knee. Sudden stretching of the leg may tear the muscle, especially in older people. Any knee disorder that brings pain or swelling, such as arthritis or a sports injury, limits the full extension of the leg

This causes the quadriceps muscle to begin to waste away, making the leg feel as if it is giving way when weight is placed on it. The physiotherapist will teach you exercises to help build and strengthen the muscle. They may also recommend hydrotherapy to help with mobility.