The quadriceps muscles 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.
They are located in different positions on the front of each of your tights.
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. 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 patellofemoral 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 hamstrings are weaker than your quadriceps.
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.
*Paresis refers to the condition of partial paralysis or weakness. Patients who suffer from spinal cord injury or a stroke often have paresis of an arm or leg. Irritation or pinching of a peripheral nerve may also cause paresis.
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 physical therapist 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.
Can I Perform Exercises for My Quadriceps?
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:
Strength: Since the quadriceps muscles cross both the hip and the knee, exercises that involve the knee and the hip are essential to improving the strength of the quads. Simple knee strengthening exercises will target the quads, and advanced hip strengthening exercises will also include quite a bit of quadriceps work.
Flexibility: There are many easy stretches to do to improve the flexibility of your quadriceps muscles.
Balance and proprioception: Balance and proprioception exercises often focus on the quadriceps since these are essential in keeping you upright and balanced. Basic balance exercises can also help to prevent falls, and advanced balance exercises may be used to help treat quad injuries and knee pain.
(Proprioception is the medical term that describes the ability to sense the orientation of your body in your environment. It allows you to move quickly and freely without having to consciously think about where you are in space or in your environment. Proprioception is a constant feedback loop within your nervous system, telling your brain what position you are in and what forces are acting upon your body at any given point in time)
Are your quadriceps muscles tight?
If they are (as they tend to be in most people), they may be creating a chronic posture problem.
There are two main mechanisms by which this can occur, and quite often both are at play at the same time.
First, by pulling the front of the pelvis down, tight quads can lead to tight and painful lower back muscles. Second, tight quads can contribute to weak hamstring muscles. Hamstring muscles are the quads' opposing muscles; they are located at the back of your thigh.
Both scenarios can affect your pelvic alignment, which in turn, may affect your posture and pain levels.
Here is what happens.
Tight Quads Pull the Pelvis Down
The quadriceps are front-of-thigh muscles. One of the four muscles that comprise this group—the rectus femoris—attaches to the pelvis at a place called the anterior superior iliac spine (ASIS). This means the rectus femoris is the only one in the quadriceps group that crosses over your hip joint (and affects movement there).
Keep things simple by thinking of your ASIS as the front part of your hip bone. For your reference, the ASIS is a place you can actually touch.
When the quads (and especially the rectus femoris) get really tight, they pull on the hip bone, which in turn tips the whole pelvis downward, or forward, into a position technically called anterior tilt of the pelvis.
Because the spine wedges in between the two halves of the pelvis, if the pelvis is brought into an abnormal forward tilt by your tight quads, the lumbar spine can adopt more curvature than it is supposed to have.
This tends to increase the arch in your lower back. An increased lower back arch, technically called excessive lordosis, is often accompanied by very tight (and painful) back muscles. Tight quadriceps muscle also may result in weak or overstretched hamstring muscles.
Tight Quads Overpower Hamstrings
At the hip, the hamstring muscles attach on your sitting bones (the small bones you can feel when you sit a lot). If you have good posture in general, most likely there's enough tone in your hamstrings at any given time to pull your pelvis down a bit in the back. This is a good thing because it helps keep the pelvis in the best position possible.
But much of this back-protecting muscle tone can be lost if your quadriceps are tight. When your quads are too tight, as the pelvis is pulled down in front, there is a corresponding lift up in back, near where the sitting bones are. This puts the hamstring "on a stretch," as therapists like to say.
If you don't strengthen your hamstrings and stretch your quads, most likely the hamstrings lose their ability to support your ideal pelvic and spinal positions.
Knowing When You Have Tight Quads
Because of our sedentary culture, and in particular how much time we spend seated every day, most of us have tight quadriceps. The more time you spend in a chair, the tighter these—as well as your lower back muscles—will likely get.
Other than that quick lifestyle evaluation, how do you know if your quads are too tight?
Here are a few screening tests you can give yourself:
Try standing up and push your hips forward. (Push from your sitting bones in order to target the correct level.) How far forward can you go and what does that feel like? If you have pain and/or limitation, you may have tight quadriceps.
If you are able to assume a lunge position where one leg is forward (and bent) in front of the other, and the back leg is straight, ask yourself the same question as in #1. What does it feel like at the front of your hip of the back leg?
If you do yoga, yet another way to tell if your quads are too tight is to reflect on your Warrior II pose. This is a standing pose in which your front leg is bent and your back leg is straight. If you have tight quadriceps (and psoas) muscles, you'll likely feel it in your back leg in this pose.
The Camel pose puts the quads on a stretch. From a kneeling position, arch back gently with the ultimate goal of grasping your ankles behind you. Modify the pose to accommodate any pain or joint issues. If you need to prop up and modify the pose a lot in order to tolerate the pain, chances are your quads are tight.
If you can easily touch your toes while bending at your hip joints (and not your lower back), this is another possible sign that your quads may be too tight.
Maybe All You Need Is a Good Stretch
One thing that tightens up the quad muscle more than just about anything is time spent being sedentary. (Hint, hint: Computer work and sitting in front of the TV.) And prolonged sitting keeps your hips in a static position, which tends to decrease hip range of motion, and may lead to hip arthritis.
Tight quads due to an overabundance of sitting can also lead to low back pain. As constantly contracting quads tug on the front of the hips, they move both pelvis and lumbar spine forward, accentuating the lordosis, or arch in that area. Tight back muscles, pain, and posture problems may result.
In most cases, the fix for tight quadriceps is simple enough: Stretch them!