Question: The Quadriceps and Back Health - How Do They Relate?
Are your quadriceps muscles tight? If they are (as they tend to be in most people), they may be creating a chronic posture problem that includes pain related to tight lower back muscles. Overly tight quadriceps muscles may alter the placement of your pelvis by pulling on it. They may also (indirectly) result in weak hamstring muscles, the muscles located at the back of your thigh. All of this affects your pelvic alignment, which is an important key to a pain-free lower back.
Here’s what happens:
The quadriceps muscles are the big, bulky muscles located at the front of your thigh. Like the hamstrings at the back of your thigh, the quadriceps are known as "2 joint muscles." In other words, they attach at the hip and they attach near the knee. In this way, their work not only influences the individual joints to which they attach –- the hip and the knee –- but also regionally by means of a phenomenon that kinesiologists call the kinetic chain. The kinetic chain refers to the way in which the movement of one part of the body affects other areas of the body. The idea of the kinetic chain plays out in a lot of ways, but two spine related examples are described below:
Tight Quads Pull the Pelvis Down
The quadriceps attach on your hip bones, at a place technically known as the anterior superior iliac spine, or ASIS for short. 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 get really tight, they pull on the hip bone, which in turn pulls on the whole pelvis. This pulling tends to tilt the pelvis downward, or forward, into a position technically called anterior tilt of the pelvis.
Because the spine wedges in between the two hip bones in back of the pelvis, as the pelvis is brought into a forward tilt by your tight quads, your lumbar spine goes with it. 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 Over Power Hamstrings
At the hip, the hamstring muscles attach on your sitting bones, those small bones you can feel when you spend a lot of time in your chair. In other words, sitting bones are located on the underside of your pelvis. If you have good postural alignment in general, most likely there is enough tone in your hamstrings at any given time to pull your pelvis down a bit in back. This is a good thing, and it contributes to lower back health.
But much of this back-protecting muscle tone can be lost if your quadriceps are tight. This is because 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 stay like this over time, the hamstrings lose their ability to support your ideal pelvic and spinal positions.