What Are the Quadriceps Muscles?

Your PT Can Teach You All About Your Quad Muscles

Woman stretching the front of her quad.
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The quadriceps are a group of muscles on the front of your thighs. As you may guess from the name, there are four distinct muscles that make up the quadriceps muscles.

The four quad muscles have individual names and are located in different positions on the front of each of your tights. These names are: 

  • Vastus intermedius. This is the deepest of the quad muscles, located below the other three.
  • Vastus medialis. This muscle is located on the inner portion of your thigh and ends near your kneecap as the vastus medialis obliqus (VMO). A weak VMO is often associated with poor kneecap position and knee pain.
  • Vastus lateralis. This quad muscle is located on the lateral, or outer. portion of your thigh.
  • Rectus femoris. The rectus formis is the superficial muscle on top of your thigh between the vastus medialis and laterals.

The quadriceps are also known simply as the quads, so if you hear someone speaking about the quads, this is the muscle group they are referring to.

What Does the Quadriceps Do?

If you sit in a chair and straighten your knee a few times, you can see and feel the quads in action on the front part of your thigh. When your quads contract, they straighten your leg at your knee joint. Since the quadriceps extend over the kneecap (patella), they also help to keep your kneecap in its proper position in a groove at the end of your thigh bone. One of your four quad muscles (the rectus femoris) also crosses the hip joint and can assist in flexion, or bending up, your hip.

Common Injuries to the Quadriceps

Injury to the quad muscles can and do occur. Your quadriceps are a large muscle group, and they are responsible for generating quite a bit of force to keep you walking, running, and stair climbing. Since your quads also keep your kneecap in the correct position, they may be subjected to repetitive stresses and forces that can cause injury.

Injuries to the quadriceps may include:

  • Kneecap dislocation. Sometimes, your quad muscle tears off the bone just below the kneecap, resulting in a dislocated kneecap. This is almost always the result of trauma, such as a sports injury or fall. If this occurs, surgery is often performed to repair the torn quadriceps. After surgery, you may have to wear a knee brace and attend physical therapy to return to normal activity and function.
  • Patellofemoral stress syndrome. If you have knee pain or swelling from an injury or if you have arthritis, the quadriceps sometimes stops working properly. This may result in a condition called patella femoral stress syndrome. This happens when the quads are unable to help keep the kneecap in its proper position, resulting in pain and difficulty walking or running.
  • Iliotibial band friction syndrome. This condition is caused by an irregular rubbing of your iliotibial band as it crosses the lateral side of your kneecap. This may happen if your quads are weak or tight and can cause pain and limited function in your walking or running ability.
  • Paresis and paralysis. Your quadriceps may become weakened due to spinal cord injury or stroke (neurological weakness in a muscle is a condition called paresis). Low back pain may result in a pinched nerve at lumbar level 3 that may cause weakness in the quads. This is usually a severe condition, and you should see your doctor right away to assess the situation and get this taken care of.

If you are having difficulty with any part of your thigh or knee and feel your quadriceps may be the cause, a visit to your doctor or PT may be in order to get things checked out.

Loss of Function from Injured Quadriceps

If you injure your quadriceps muscle or muscles, you may have difficulty with functional mobility. You may be surprised to learn that your quadriceps muscles help you move around in bed. They contract to help you scoot your bottom while lying down, and they can help you roll in bed.

The quadriceps muscles also are very active when rising from a chair. They help to straighten the knee, which is essential to rise up from a sitting position. The quads are also a major muscle group responsible for walking up and down stairs.

As you may have guessed, the quadriceps muscle group is also essential for walking and running. The quads help keep you moving forward while walking and running, and they prevent you from falling when standing still. Weakness in the quads may result in gait abnormalities, and you may require an assistive device like a cane or walker to help with normal walking if your quads are not working properly. Your physical therapist can help you decide which device is right for you if you need one after a quad injury.

Can I Perform Exercises for My Quadriceps?

If you suffer an injury to your quadriceps, your doctor may refer you to physical therapy to help improve functional mobility and to improve the strength and flexibility of the quadriceps. Your physical therapist can offer suggestions for the correct exercises for you to perform to help your specific condition.

Basic knee mobility exercises focus on quadriceps strength and mobility and stretching exercises for the quads help to improve the flexibility of the muscle group.

The main types of exercises that you can perform to help improve the function of your quadriceps include:

Be sure to check in with your doctor or physical therapist before starting any exercise for your quads.

A Word From Verywell

If you feel pain in the front of your thigh after an injury, you may have done something to your quadriceps. Often, injuries to the quads are easy to rehab; a little rest and some stretching are all it takes. Other times, a quadriceps injury can be serious, so check in with your doctor in you have injured the front of your thigh. An injury to your quadriceps can be a painful experience. A visit to your physical therapist may be the key to helping you improve the function of your quadriceps to get you back to normal functional mobility quickly and safely.

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Article Sources
  • Çelik, D., Argut, S. K., & Kılıçoğlu, Ö. (2017). The effectiveness of quadriceps strengthening exercises combined with Neuromuscular Electrical Stimulation on patellofemoral pain syndrome: Pilot study. Physical Therapy in Sport28, e16.
  • Lichtenstein, A. H., & Fine, J. (2017). Quadriceps Te ars and Tendon Ruptures. In Musculoskeletal Sports and Spine Disorders (pp. 277-279). Springer, Cham.