Whether people pray to Jesus, Allah, God, or another deity, it’s common for them to use their bodies in ways that show devotion. That often means various positions of kneeling, bowing, or prostration. Christian prayer often involves different degrees of kneeling (called genuflection when only one knee is bent). In Judaism, davening involves repeated bowing at the waist while standing in prayer, often while bending the knees. Muslims are supposed to pray (salah) every day at five prescribed times, in a kneeling, bowed position, when physically possible. And people who engage in yoga or certain other spiritual or meditative disciplines use some kneeling, prayer-like postures as well (for instance, the forehead-to-the-ground “child’s pose” in yoga). Can these body movements be risky, especially for the back, hips, and knees?
Call to prayer
To many non-Muslims, traditional Muslim prostration during prayer—kneeling and then bowing to touch the forehead to a prayer rug on the ground—may seem like a marvel of dexterity. It’s logical to wonder what it does to the body. To assess the biodynamics of typical body positions during Muslim prayer, researchers used digital computer modeling software in a recent study in the International Journal of Industrial and Systems Engineering. Though they didn’t actually measure stress and forces on the bodies of actual people, their findings suggested that this kneeling position can increase elasticity of the knee joint, while the bowing (flexing) position, though potentially stressful on the lower back, can still be safely done by healthy people and, if modified, by those with back pain. For instance, the investigators suggested that altering the angles of the knee and back (by flexing the torso at less than a 90-degree angle while also bending the knees a bit) could reduce low back pain.
Different ways to kneel and bow
When taking such praying positions, it helps if you’re used to them and are flexible and fit to begin with. In addition, different ways of kneeling have different effects, as can different speeds. Genuflecting on one knee actually puts more stress on the knee than kneeling on both knees (at 90 degrees, as you would when, for example, receiving Communion). Kneeling and sitting back and down on your lower legs (knees bent more than 90 degrees, called deep flexion) is most stressful.
Bowing can overly stress the back, depending on how deeply you bow (back flexion) and whether your knees are bent or not. For example, deep flexion of the spine when bowing, especially bowing more than 90 degrees when the knees are straight, puts excess stress on the spinal discs and ligaments. And rapid bowing is more likely to injure discs than slow movement.
Of course, back pain is not a uniform disorder. Some people with back problems have more pain when bending forward as in prayer (flexion), others when bending even slightly backwards (extension). For people whose back pain becomes worse with flexion, including those who have had hip replacement, it's best to avoid a seated forward bend pose where they sit on the floor with full back flexion.
A mixed blessing
More research is needed on the physical demands of various types of kneeling and bowing in prayer, especially in people with musculoskeletal problems or disabilities. If you have knee, back, or hip problems, kneeling or bending over in prayer (or any similar activity) can be a challenge. For people who are unable to stand or kneel for physical reasons, religions allow seated (or even lying down) praying alternatives.
Here are some things to try if you have problems when kneeling while praying. Avoid full kneeling and shift your position as much as possible. Gel-filled knee pads or cushions may help by dispersing the load. To reduce strain on the lower back when bowing, keep your knees slightly bent, avoid full 90-degree bowing, and move in a gentle, controlled manner. If you have pain or discomfort from your customary prayer position, a physical therapist may be able to advise you on how to modify it as well as provide stretching and strengthening exercises that may help answer your prayers.
Also see What to Do About Low Back Pain.