Article Written By Cindy Dallow, Ph.D, RD
Registered Dietitian and Certified Specialist in Sports Dietetics (specialty within the American Dietetic Association)
Big believer in “health at every size” and helping women get off the couch, off the scale, and out the door!

A few years ago a friend of mine experienced horrible muscle cramps in his calves during the latter part of his first marathon. He ended up walking the last six miles. He was stunned; all of his training runs had gone well and he had never had muscle cramps before. Although happy to finish, the experience was not what he hoped for.

Numerous stories like this abound in the running/triathlon community. The cause of muscle cramps, many people believe, is sodium depletion from excessive sweating. They compensate by consuming large amounts of salt tabs in their next race or by drinking chicken broth, pickle juice, or some other awful-tasting, high sodium beverage.

Others feel dehydration is the culprit of muscle cramps which they resolve by drinking copious amounts of water during their big race, only to end up in the port-a-potty at every aid station.

The good news is that muscle cramps are not due to sodium depletion or dehydration. According to Dr. Jason Karp, owner of www.runcoachjason.com, and 2011 Idea Personal Trainer of the Year, muscle cramps are due to an increase in running pace and premature muscle fatigue. The combination of these two events negatively impacts the nervous system’s ability to relax a muscle after it has contracted.

Muscle cramps occur more often in muscles that cross more than one joint, such as the gastrocnemius (calf) muscle, which crosses the ankle and the knee, and the biceps femoris, which crosses the hip and knee joint. They tend to happen when runners run farther or faster than they are used to, which might be why they occur more often during a race than in a training run.

What to do if you experience a muscle cramp during a race? Stop and passively stretch the cramped muscle or try voluntarily contracting the muscle that opposes the cramped muscle. For instance, if your hamstring starts to cramp, try contracting your quadriceps, which will help the hammies to relax.

In addition, try not to suddenly increase your pace in a race if you’re not used to that kind of pace, esp on a hilly course where hamstring and calf muscles are contracting frequently as you run up and down the hills.

As a sports dietitian, I’d love to say that muscle cramps can easily be prevented by consuming more sodium or drinking more water but I can’t. On the other hand, it’s nice to recommend eliminating (or reducing) the amount of nutrition products you need to carry during your big race and focus more on knowing what to do if cramping happens. High sodium products do have their place (long races in the heat for people who are heavy sweaters) but if its muscle cramping you’re worried about, you can ditch the salt tabs and practice the “stretch and contract” method instead.