Hip extension is the backward movement of your thigh. This movement is used in many daily activities. Muscles that perform hip extension are active when you stand up from a chair, walk, run, jump, roll over and climb stairs. They also play an important role in maintaining proper posture. Tightness or weakness can develop in these muscles, particularly if you spend a lot of time sitting during the day. The main muscles used in hip extension are your gluteus maximus and hamstrings.
The gluteus maximus is the main muscle that performs hip extension. Most people refer to this muscle as their buttock. It connects your tailbone to your thigh bone, and one of its main functions is to help you stand upright. When your heel hits the ground as you walk, the gluteus maximus also helps stop your body from continuing forward by stopping the hip from flexing.
Three muscles called the semitendinosus, semimembranosus and biceps femoris make up your hamstrings. These muscles run along the back of your thighs and are easily injured or strained. They run from your pelvis to the back of your knees and together work to stabilize the hip joint. The hamstrings are the primary muscles that perform hip extension during normal walking. In addition to hip extension, the hamstrings also bend your knees. These muscles propel your body forward and increase your walking speed.