Muscles and Knee Pain

Tests and Treatment for Rectus Femoris (Quadriceps)

Knee Pain Due to the Rectus Femoris Muscle

Symptoms. Pain in the front and center of the knee, particularly when walking downstairs or downhill, or when wearing high heels. Difficulty extending the hip or fully flexing the knee.

There are also leg locks and pins that specifically take advantage of tight quads.

(Note: The vastus intermedius muscle, lies beneath the rectus femoris. This "forgotten quadricep" tends to cause more problems walking upstairs or up hill and refers pain to the upper thigh. When tight, these two muscles together can cause the hip to buckle when you straighten your knee and step back.)

About the Muscle. This common problem originates in the rectus femoris muscle in the front of the thigh. The rectus femoris (one of the quadriceps muscles) runs from the front edge of the pelvis down to the front of the shin, just below the knee. (The "X" in the picture indicates the most likely trigger point, but notice that the pain is concentrated on and just above the knee, far from where the pain actually originates.)

When this muscle is tight and shortened by trigger points (areas where fibers are abnormally shortened) it tends to pull the pelvis forward, creating a "sway back," an anterior (forward) rotation of the pelvis. It also forces the knees back into hyper-extension, causing strain on the cruciate ligaments of the knee as well as other muscles and connective tissues.

The sway back or "bubble-butt" figure is very commonly seen in female gymnasts and ballerinas, in soccer players and others who develop powerful thigh muscles especially in those who conscientiously stretch out their hamstrings.

Think of the pelvis as a pulley. The quads pull down on it from the front. The hamstrings pull down on it from the back. Ideally there is a balance between the two muscle groups. But . . . when rectus femoris is tight it will rotate the pelvis forward. Simply stretching out the hamstrings alone will increase any problems with anterior pelvic tilt. To avoid this, rectus femoris must also be stretched. Unfortunately, because the rectus femoris crosses two joints (hip and knee), it is rarely stretched out fully.

Testing for Rectus Femoris Problems

Test 1: The Swayback Test

A quick test for a tight rectus femoris is the Swayback Test.

Lie on your back on a firm surface with your legs straight. Relax. Imagine for a moment that you are lying in warm sand at the beach.
Is there room to slide a hand? - an arm? - between back and sand?

While there may be a little space, too much space, such as space for a hand, or (worse) a whole arm, is not good. The more space beneath the small of the back, the more likely that there is anterior rotation of the pelvis, hence problems with the rectus femoris muscle.

Test 2: Heel-To-Butt Test

To test for tight rectus femoris, with help from a partner,

1. Lie on the side of table or bed with hip and knee hanging slightly over the edge. (Flex the other knee as shown to protect your lower back.)
2. Have your partner bring your heel slowly and gently toward the same-side buttock. Ideally heel should touch buttock, but do not force it; move the heel only until resistance is felt. The farther the heel from the buttock, the tighter the rectus femoris muscle. If you are short by a couple feet and have kneecap pain with no apparent structural damage, you may have found the reason.

   If you fail this test and are in wrestling, Brazilian Jiu-Jutsu, mixed martial arts, or other styles with ground techniques, you will be extremely vulnerable to leg locks.

   Fortunately this is one of the easiest muscles in which to produce quick improvement.

Treatment

Pressure Treatment

A rectus femoris with decreased range of motion probably contains trigger points. To self-treat this muscle:

2. Place same-side elbow a few inches above the middle of your knee cap.

3. Gently press into the muscle at various points from the knee up to the attachment point on the pelvis. Trigger points are most commonly found in the upper portion near the hip. Note that trigger points always hurt when pressed, but not everything that hurts is a trigger point. Feel for distinct areas of swellings or nodules. These areas may range in size from a pea to a walnut.

4. Hold gentle pressure on the tender area until the pain subsides.

Notice in the pain pattern diagram that the main trigger point is just below the muscle attachment near the hip. For that point, it is easiest to have a partner apply pressure. Or, to self-treat, you can place a tennis ball on the floor or wall and lie or lean against the point. Remember, gentle (but firm) pressure is best!

After pressure treatment, the muscle must be stretched.

Stretching

Once you have treated the muscle, stretching should be done at least once every (waking) hour for several days. Stretching should not hurt. Do each stretch 3 times, holding each one for 3-5 seconds. Always treat and stretch the muscles on both sides.

1. Repeat the range-of-motion test, pulling heel toward the same-side buttock. (Don't twist the knee.)
2. Repeat, pulling heel towards the opposite buttock. Remember, the hip must be straight or extended back. If the hip is flexed (as is so commonly done), you are stretching the vastus muscles only, not the rectus femoris.