It probably comes as no surprise to regular readers of this column that knee pain ranks at the top of the list of running injuries. The most common of these is patellofemoral pain syndrome (a.k.a. runner’s knee, chondromalacia patella, anterior knee pain syndrome, patellar osteoarthritis). This ailment is essentially a form of degenerative arthritis, in which the thin layer of protective cartilage on the inside of the knee cap begins to wear away, leaving the pain-sensitive bone beneath it vulnerable to the compressive pressures from activities such as walking, stair-climbing, squatting, and of course, running.
Arthritic changes in the “other” knee joint – the tibiofemoral joint that connects the thigh and shin – are commonly seen in the more aged population and are responsible for the thousands of knee joint replacements performed every year.
One of the consequences of this form of arthritis is a loss of range of motion in the joint over time. Typically, individuals lose the ability to flex the knee through its normal range, presumably as a result of structural changes (bone spurs, joint lining thickening) that develop as the arthritis progresses. This theory has led many to consider this loss of motion inevitable and much of the available evidence appears to support this assumption.
A recent study, however, gives reason for optimism that this does not necessarily have to be the case. Dr. G. Szabo and colleagues published a report in the Journal of Bone and Joint Surgery [2000;82-B:1167-9] last year that appears to contradict the conventional wisdom. The authors compared the range of motion of the knees of 103 individuals (151 knees) with documented (X-ray) grade-III or higher osteoarthritis. One group was comprised of Arabic Muslim patients, with a second arthritic group that included non-Muslim patients from Hungary. A third control group contained Arabic Muslim individuals without arthritis (51 subjects/51 knees). All of the groups were similar in age and had comparable numbers of men and women.
The research team chose the Arabic Muslim group because of the traditional Arabic posture for prayer that forces the knees into deep flexion for extended periods several time a day. The hypothesis of the team was that the deep flexion postures would preserve mobility in patients with osteoarthritis, and the study’s findings appear to confirm this. Not only did the Arabic Muslim group have significantly greater range of motion (137.5°average) than the non-Muslim group (96.5°), they also showed comparable range to the control group without arthritis (145.5°)!
While this study admittedly has some significant design flaws, its preliminary findings are certainly intriguing and worthy of further investigation. And while it also fails to address whether this improved flexibility in the arthritic group translated into greater functional abilities and/or reduced pain compared to the non-Muslim group, it seems reasonable to me to be make that tentative assumption.
I also think that while this study examined the tibiofemoral joint exclusively, there may be some applicability of these findings to the aforementioned patellofemoral variety of osteoarthritis found more often in runners. Perhaps deep flexion range of motion exercises and postures, such as that found in the Muslim prayer position, could provide some benefits by improving supportive soft tissue flexibility as well as by more equally distributing the non-weight bearing, nourishing compressive forces on the patellar cartilage.
Of course, if you decide to try this, be sure to do it religiously (i.e., pray it works!).