Conway McLean, DPM, Journal columnist

You’re lying in bed, warm, relaxed, finally shedding the tension of your day, drifting off to sleep. Suddenly, quite forcibly, your calf muscle contracts sharply, uncontrollably. An alternate scenario: a soccer player, an hour into an intense match, falls to the ground, dropped by a “charley-horse.” Most athletes have experienced the pain of muscle cramps at some stage during their sporting career. But these are different from the sudden cramping that rouses someone suddenly (and painfully) from their sleep. It turns out there are numerous examples of muscle cramps, the spontaneous, involuntary contraction of a muscle group.

The muscle is contracting without your intention, unbidden and undesired. Hence the term “involuntary,” which includes an inability to relax the structure by mentally trying. Although relatively harmless, muscle cramps can make it temporarily impossible to use the affected muscle. And they are significantly painful while in the midst of the contraction. They don’t cause swelling of the region, nor redness. If either of these changes are seen, it is a different and more serious condition.

Age also seems to be a predisposing factor, the years leading to more common problems with cramping. These may develop later in life in people who exercised for years without any cramping problems. Alternatively, long periods of exercise in whatever form, especially in hot weather, may cause muscles to cramp. These are one of the primary categories of cramping: exercise-induced or non-exercise induced.

This tendency for exercise to cause cramping is believed to be due to the depletion of various minerals important in muscle contraction. These include inadequate levels of potassium, calcium, or magnesium. Some medications promote them, especially diuretics, as do certain medical conditions, like Parkinson’s, diabetes, kidney disease, clogged arteries, and liver disease. Other factors that apparently are important include increased body weight and improper footwear. 

As is usually the case in nature, there are multiple components to the process leading to cramps, including your electrolytes, your hydration levels, and numerous others. Simply having inadequate levels of hydration does not appear to reliably lead to cramping. Some individuals seem to be genetically susceptible to them, current research indicating it is due to the type of collagen in tendons.

Increased running speed has been shown in clinical studies to be associated with increased incidence of cramps. Therefore, we may assume increasing the functional demands on a muscle group can be a reason for cramping. But does it have to be a highly conditioned athlete or could it be your average senior citizen?

It is well accepted in the medical community that the small muscles in the hand can be afflicted with cramps in those performing repetitive tasks, such as typists or writers. Also well-established is the stress to many foot structures in those with inefficient foot mechanics, which may be the case when an individual suffers from a flatter foot architecture. This is also true with ligamentous laxity (a medical term for someone with ‘loose ligaments’).

Having been in practice over 30 years, cramping in the arch is a common complaint, and not always associated with plantar fasciitis (although many assume any arch pain must be plantar fasciitis). Some people have less than optimal foot mechanics, meaning many of the muscles in the foot are working too hard, and too much of the time. If exercise is known to instigate cramps in an athlete, why wouldn’t they in the non-athlete? I believe this is the case with the pronated foot, a common foot type in which the arch lowers too much.

There are numerous small, separate muscles in the foot, important in the strenuous functions served by the human foot, especially standing and walking. I would propose a similar mechanism for the development of cramping pain in the arches, a condition experienced by many. Although no definitive study has been published, anecdotal evidence reveals relief is often obtained through foot exercises, appropriate stretching, and some kind of arch support.

Ultimately, the underlying mechanism of muscle cramping is poorly understood, with little definitive knowledge of the root cause for these painful attacks. Our currently accepted medications for muscle cramps treat only the symptoms. Anything more than that is difficult when the root of the problem isn’t understood. Interestingly, also unknown is the association of poor foot and leg biomechanical function with foot cramping. No adequate study has yet examined the effect of improved foot and lower extremity biomechanics on this condition.

New research indicates the cause of cramps most likely involves hyperactivity of a nerve-muscle reflex arc, a circuit made by particular nerves running to the spinal cord and back to the area, but we do not understand how this process occurs. Studies have reported a variety of causes of cramping of the type related to exercise. But, regardless of the cause, cramps are notoriously unpredictable, making good studies difficult.

Along with the critical step of relieving pain from damaged or aged structures, some combination of a precise stretching regimen, strengthening of appropriate muscle groups, and the use of foot supports, has improved the lives of many people. These are beneficial objectives, but not easily achieved. The pain of recurrent cramping of the arch or calf can be debilitating. Perhaps a better understanding of human physiology and biomechanics would provide better answers. Once again, we can earnestly say, further study is needed.

Editor’s note: Dr. Conway McLean is a physician practicing foot and ankle medicine in the Upper Peninsula. Dr. McLean’s practice, Superior Foot and Ankle Centers, has offices in Marquette and Escanaba, and now the Keweenaw following the recent addition of an office in L’Anse. McLean has lectured internationally, and written dozens of articles on wound care, surgery, and diabetic foot medicine. He is board certified in surgery, wound care, and lower extremity biomechanics.