Although ''show'' muscles such as biceps and abdominals tend to get more attention than others, every muscle group in your body is important for optimal health. Among the largest muscle groups on your body are the hamstrings and quadriceps. These two muscle groups help you do everything from perform complex sports maneuvers such as a bicycle kick to simply enabling you to walk down the street. The hamstrings and quadriceps work together, but they have many differences that are noteworthy.


The hamstrings are located on the back of the upper leg, and the quadriceps are located on the front of the upper leg. The hamstrings run from an attachment point just below the knee all the way up to the pelvis. The quadriceps attach to the skeleton at the patella, or kneecap, and run all the way up to the pelvis. This anatomy makes the quadriceps and hamstrings among the longest muscle groups in the body.

Muscles in Each Group

As the name suggests, the quadriceps contain four muscles. The hamstrings muscle group comprises just three muscles. The muscles of the quadriceps are the rectus femoris, vastus intermedius, vastus lateralis and vastus medialis. The muscles that make up the hamstrings are the biceps femoris, semimembranosus and the semitendinosus.

Functions of Each Muscle Group

To perform a series of movements -- such as that required for walking or kicking -- the hamstrings and the quadriceps work together. However, each muscle group performs different functions. The main functions of the hamstrings are to extend the knee joint, straightening the leg, and to extend the leg at the hip, causing it to move backward. The quadriceps flex the leg at the knee by causing the knee to bend and also flex your leg at the hip, causing the leg to move forward.

Injury Prevention

Because the hamstrings and quadriceps perform such important functions, avoiding injuries is crucial for athletes. Lack of strength and conditioning and tightness can cause injuries, so performing strengthening exercises and stretching can help you avoid strains. You can keep your hamstrings strong with leg curls and Romanian deadlifts, while the leg press and leg extensions can help strengthen your quadriceps. Always warm up with stretches before athletic activities to reduce the risk of strain.

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