Featured photo: Fertile ground for muscle cramps… high intensity criterium racing.
Bent over our handlebars, hearts pounding, the spectators on the shoulders are a blur. There are four of us in the lead breakaway pack; our bicycles inches apart. Seven hundred yards ahead is the finish line for the 2020 Minnesota Senior Games Men’s 40 Km road race. Over the last five miles, I have been battling not only the other riders, but cramping in my left calf. This is not the first time my calf muscle has cramped. The sprint for the finish two hundred yards away begins. I’m in perfect position— right on the leader’s rear wheel. Then my left calf cramps and locks up. I drop back. No podium finish today.
For almost a century, we have been taught that exercise associated muscle cramps are due to dehydration and loss of electrolytes like sodium and potassium from prolonged sweating. However, modern science fails to back this up. First proposed in the 1990s, an alternative theory says cramps are caused by neurological issues resulting in a sustained abnormal discharge of motor drive to excessively fatigued muscles. Each of these theories has some validity.
In my research to understand muscle cramps, I have found a lot of folklore and little real understanding. In this article, I will explore what I learned about cause and prevention of muscle cramps.
Muscle Cramps Defined
A cramp is the sudden squeezing or contraction of a muscle lasting seconds to minutes, often with a palpable hard knot in the effected muscle. On electromyogram, the involuntary muscle contraction is associated with repetitive firing of muscle motor units. The number of motor units activated and the frequency of discharges increase gradually during the cramp; then decrease gradually with an irregular firing pattern toward the end of the cramp. While research has clearly demonstrated cramps originate within the motor nerves, the cause of cramps is still open to debate.
Types of Cramps
Recurrent, nocturnal leg cramps can occur in any age group. The cramps typically involve the foot or calf muscles. Their effect on sleep and quality of life can be pronounced. Research indicates they may be associated with the loss of motor neurons in the muscle as we age.
There are a number of health disorders associated with muscle cramps: pregnancy, liver and thyroid disease. In certain cases, elevated cramping risk can be hereditary.
Exercise-Associated Muscle Cramps or EAMC have been observed in both training and competition in almost every type of sport. Cramps occur both during and after activity. In this article I will focus on Exercise-Associated Muscle Cramps or EAMC.
Cramp Risk Factors
There have been a number of studies on both marathon runners and triathletes. Major risk factors found are underlying chronic disease and medication use. Cramping is more common in older and more experienced athletes. Cramps are associated with training, competing, and working in hot and humid environments. Also significant is a record of prior cramping or injury in muscles that cramp. Cramps are also found in muscles subject to higher levels of stress, power output and training loads without adequate recovery.
In my experience as an athlete and trainer, I have found cramps to be associated with all of these factors. There is no one risk factor and, as I will point out in the next section, no one cause.
Possible Causes of EAMC
Two main causes of muscle cramps have been proposed. The evidence supporting one theory for all cramps is weak. It is unlikely that there is a single cause or a single strategy for prevention and treatment.
The first theory holds that cramps are caused by a combination of dehydration and electrolyte depletion. As athletes, we were all taught to drink copious amounts of water and take our salt pills. There is a long history of folk remedies for cramps including pickle juice, mustard, quinine, and vinegar. These remedies are accompanied by testimonials from athletes being used to promote these products. Research supporting these theories is difficult to come by as cramps generally resolve themselves quickly.
There are large population studies on industrial workers in the 1920s and 1930s that found administering of saline drinks and salt tablets reduced the incidence of cramps. The cause of these cramps where hot and humid conditions, excessive water consumption and continued hard work. Recent studies on athletes are limited to small populations. There is some evidence that athletes who lose large amounts of salt in sweat are more prone to muscle cramps. However, cramping occurs in cool environments suggesting that sweat loss and electrolyte balance cannot account for all cramps.
Evidence emerged in the 1980s and 1990s that cramps often occurred during exercise in absence of substantial sweat loss or gross disturbances in electrolyte balance. The theory emerged that cramps are caused by altered neuromuscular control. Muscle spindles and the Golgi tendon organ are components of the nervous system that function with each other to regulate the stiffness of the muscle. Increased activation of a fatigued muscle causes a malfunction in these two components causing an uncontrolled reaction or muscle cramp.
Rather than rely on an either/or approach, there are good reasons to suggest different mechanisms may apply in different situations.
Preventative and Treatment Strategies
In my experience, some cramps are related to sweat loss and electrolyte imbalances in hot and humid weather. Adequate, but not excessive hydration along with high quality salt tablets or electrolyte drinks helps prevent cramps.
I also believe cramps are related to neuromuscular control. Contributing factors are a history of cramps which makes a muscle more prone to cramping. Muscle fatigue and excessive stress cause cramps. In my sprint to the finish, my calf muscle were already fatigued. In moment of high stress, I tend to draw more power from my left leg. It was my left calf that cramped. Being aware of muscle fatigue and consciously relaxing your muscle can prevent the onset of cramping.
I have clients who have peripheral neuropathy due to damage of nerves in the feet. They experience excruciatingly painful and debilitating cramps. We have achieved some relief by static stretching and taking a Calcium Magnesium Citramate supplement.
I am also susceptible to nocturnal cramps after a long day at the gym training clients or a hard training day. Sometimes it’s my foot; other times my back or even my hand that cramps. Taking a Magnesium supplement and taking time to stretch, relax and meditate before bed helps prevent these nocturnal cramps.
If you suffer from chronic cramps, document your activities that lead to cramping. Try one or a combination of the above strategies.
I round the curve into the last straightway to the finish. It is August 15th, 2022 and I am competing in the Minnesota State Senior Games 10K Time Trial cycling race. My left calf is starting to cramp. I relax, lighten the power to my left pedal increase power to the right. For the first time the wind is to my back. My speedometer reads 28 mph. I’m flying. I got this. I cross the finish with no cramp. It is a gold medal effort. No one is even close; second place finishes over 40 seconds behind.
Photo: Podium. Men’s 65+ Time Trial, 2022 Minnesota Senior Games.