This video shows the hip flexor – rectus femoris stretching. The Rectus femoris muscle is one of the four quadriceps muscles that sits in the middle of the front of the thigh. It is responsible for knee extension and hip flexion. It is considers one of the muscles that make up the hip flexors; a group of muscles that bring the legs and trunk together in a flexion movement. Hip stretching is important because it increases your flexibility. Without some good hip flexor stretches, you will not be able to minimize the risk of injury. Find out how to avoid hip flexor injury and what are the hip flexor strain treatment.