I very often hear runners casually mention that their “sciatica is acting up.” Generally, they describe pain in the back of the thigh, maybe into the calf as well, and sometimes the buttock and lower back. Since this pretty much fits the medical dictionary definition of “sciatica,” in one sense this self-diagnosis may be for the most part correct. But is this of any real value? If, in fact, one is truly suffering from sciatica, do we now know what to do about it? No, not really.
Even a professional diagnosis tells us very little since “sciatica” is what we call a “garbage-can” term. That is, it is often used conveniently to describe general symptoms without specifying a particular underlying cause. And in the case of sciatica, there’s a whole host of suspects when trying to determine the true culprit. Let’s look at some of these.
Pain in the back of the thigh can certainly be the result of a hamstring injury, either acute or chronic. The former is not likely to be thought of as sciatica, since the trauma usually occurs while we are conscious and, as anyone who has had a hamstring tear will report, you know exactly what it is. Chronic hamstring strain, though, is most often an overuse syndrome and thus, not quite as apparent. This is a nagging, sometimes quite uncomfortable sensation, and in my experience, it is one of the most common forms of so-called “sciatica” in the runner.
Moving higher up in the leg, we find that the sciatic nerve (which is, by the way, the largest nerve in the body), while traversing the buttock, sometimes passes directly through a large muscle called the piriformis. This muscle is one of the primary external rotators of the hip joint, and if it is overused, tight, inflamed, etc., it can irritate the sciatic nerve, causing pain down the leg. Some even believe that inflammation of the muscle itself can cause these symptoms, regardless of whether or not it affects the nerve itself.
Up a little higher still is the sacroiliac joint, the connection between the lower portion of the spine (sacrum) and the iliac bones (pelvis). Various health care professionals continue to argue over the existence/fallacies/significance of the SI joint sprain, but for those who do believe it occurs (myself included), it represents an important and, in runners, quite common cause of sciatica-like symptoms with referred pain to the back of the thigh. Most often, however, the pain will also be felt on one side of the low back.
Still going up in the back, we find the structures most often thought of as responsible for “true” sciatica, the intervertebral disc. A herniated (or ruptured) disc can and generally will cause inflammation of a nerve root in the lower spine, a root that is one portion of the sciatic nerve. Irritation of the nerve root will cause the common symptoms already discussed, while compression of the nerve may also cause numbness or tingling in the foot or toes, loss of motor strength of certain leg muscles, and/or loss of reflex at the knee or ankle. A disc herniation is bad news and needs to be addressed by a professional. Anyone with the symptoms outlined just above, particularly pain, tingling or numbness below the knee, should see his/her physician as soon as possible.
The good news is that the incidence of disc herniations in the physically fit is significantly lower than the in the general population. So for the most part, runners with sciatica are dealing with one of the other problems I have described. These are less serious, if no less annoying, and should first be treated with a cutback in mileage, intensity, etc. for a few weeks. If it persists, it’s time to seek professional services to accurately assess the true nature of the problem and to treat that appropriately.