How does your lower back feel right now? How about your knees?
Two of the most common body parts that hurt are knees and backs. About 80 percent of the U.S. population will experience low back pain in their lifetime. It is the second most common medical complaint, and is second only to the common cold as the cause for lost work days. Meanwhile, incidents of knee pain have doubled in women and tripled in men over the past 20 years.
A common strategy in effectively dealing with joint pain and discomfort is to look at the muscles or joints “upstream” and “downstream”.
In many instances, there is a dysfunction in the muscles above or below a joint that is causing or contributing to the problem. In the case of knees and lower backs, they share a common joint. The joint above the knee is the hip, and the joint below the back is the hip. So if many people in a population are having problems with their knees and backs, we need to look at what is going on with our muscles around our hips.
Our muscles adapt to the stresses that we place on them on a regular basis. So what do our hips do during most of the day?
Well, for most of us, they do nothing. They sit. We sit while we eat. We sit to commute. We sit to work. We sit to surf the web and read BethesdaNow. We sit to talk to friends. Many of us even sit to exercise! What does all of this sitting do to the muscles around the hip?
Without getting too much into muscle anatomy, we’ll talk about what sitting does to the large muscles that cross over the hip joint:
Hip Flexors – Your hip flexors lift your thighs toward your torso. When you are seated, your thighs are closer to your torso than when you are in a neutral, standing position. So your hip flexors are in a shortened position when you are seated.
Imagine if you had your elbow bent all day. (If you’ve ever had a cast on your arm, you’ll know the feeling.) At the end of the day, it would be hard to straighten your elbow because your bicep muscle would have adapted to that new shortened position.
This sounds benign, until you consider that of the the muscles that comprise your hip flexors, the most powerful one is attached to vertebrae L1-L5 (also known as your lower back). And one of the other hip flexors is attached to your knee. So it is no surprise that shortened hip flexors from sitting too much will put more tension on your lower back and your knees.
Glutes – Your glutes do the opposite of what your hip flexors do. They move your thighs away from your torso and vice versa. Imagine a big, heavy-duty rubberband that runs from the bottom of your back, around your butt, and attaches to the back of your thigh. When you are standing, it is relaxed. But when you sit, it is being stretched. So when you sit, your glutes are lengthened.
What happens to a rubber band when you keep it in a stretched/lengthened position for hours a day?
It loses its tension, and its ability to produce force. Add to that, the fact that tension in one muscle causes the opposing muscle to relax. (Our muscles are hard-wired that way. Imagine what would happen if your biceps and triceps contracted at the same time. Your arm wouldn’t be able to move.) Now, all of a sudden, you’ve got gluteal amnesia. Your glutes have forgotten how to work because they are lengthened, weak, and always being told to “shut up” by your tight hip flexors.
So what does this all mean for your knees and back?
Well first, you will have this constant tension in the muscles in your lower back because they are fighting against your tight hip flexors to keep you upright. The combined result of the battle between these two muscles is increased pressure on the discs and the nerves in your lower back. Then, those amnesic glutes don’t know that they should be producing force when you reach down to pick up your kid, dog, laundry basket, groceries or you name it.