The Real Cause Of Cramp

What is the real cause of cramp?

Dr. Ross Tucker answers:

CrampsThere’s a popular misconception that cramp is caused by either dehydration or electrolyte imbalances. So if it’s not fluid-related, what is the likeliest cause?

Well, a few specific questions can help identify causes.

Two questions to ask: Where are you most likely to cramp, and when? The answer is in the muscles you are using most (in running, the hamstrings, quads and calves); and as for the when, cramping happens during races, towards the end of the event, and is more likely to happen on challenging, hilly courses.

There is also the recent finding that runners who cramp are those who are over-extending themselves relative to their training. Runners were asked to predict their performance for an upcoming race based on their training, and the likely crampers turned out to be the ones who went off too hard, racing faster than their training suggested. That leads to muscle fatigue, and happens more on challenging courses – and only in the exercised muscles.

The simple answer, then, is fatigue. At a complex level, cramping is the result of a ‘malfunction’ of sorts in the neural control of the muscle – the nerves controlling the muscle fire inappropriately, and the result is a painful muscle spasm when the muscle should be relaxing.

The solution?

Strength and pacing discipline. Strengthening delays and prevents fatigue, keeping the cramp at bay. This includes training for the race situation.

Then, pacing is crucial – don’t ask more of your muscles than you’ve prepared them for.

Dr Ross Tucker has a BSc (Med) (Hons) Exercise Science Degree and PhD from the Sports Science Institute. Visit him at

3 Responses to The Real Cause Of Cramp

  1. Rob 27 June 2013 at 12:56 pm #

    Finally, and now stop publishing articles that state that athletes should drink more water or replenish their electrolytes to avoid cramps.

  2. Sandy Mullis 27 June 2013 at 5:15 pm #

    I was ready and prepared for a 10 – 10:30 Comrades. I had trained and when I started out, my pace was not too fast. Yet the latter half from just before Camperdown, I cramped badly. So time went out the window and I ran when my legs allowed and walked the rest, finishing with 8 minutes to spare. So not quite sure why it all went so pear-shaped!

  3. Tim 28 June 2013 at 7:13 pm #

    This makes sense for running. I find that even when I’m well conditioned my foot or calf will cramp when swimming, especially in cold water. Is this still due to “neural malfunction”, aberrant mechanoreceptor firing or another mechanism?

Leave a Reply