Muscle Cramping/Science of Sport

Who experiences cramps?

There does seem to be a predisposition cramps. To date no one has even tried to identify the gene(s) that might predispose one to cramping, but even a general survey of the active population will reveal that some people cramp both at night and during exercise, while others never cramp. So you might indeed be a “cramper” before you even toe the line!

What causes them?

We have presented two models for the cause of cramps. The first model tries to explain them based on electrolyte disturbances and dehydration. The second model is based on neural activity and muscle excitation and relaxation. So which one is correct?

The short answer is that we do not know exactly what causes cramps, and it will likely be many years (perhaps even decades) before someone presents a more definitive model that better explains their cause. As we mentioned in a recent post, science is like watching one chess square and trying to create hypotheses based on observations of that one square. We have presented the available scientific evidence, and have drawn our conclusions based on that evidence. Does that make our conclusions correct? To be certain, “No not necessarily!” It merely represents our interpretation of the data.

The bottom line here is that it is a complicated mechanism, like so many others in the body. Also, just as our many different systems are affected by a vast array of factors and circumstances, so is the cause of cramps, and until we have a reliable laboratory protocol that can reproduce cramps in a predictable manner, we cannot really test the models further.

Ok, so I am a cramper. . .now what do I do?

There are a couple of key points here:

Regular stretching will help reduce the incidence of your cramps. This is because, as we explained in Part III, stretching will reduce the alpha motor neurone activity, and thus reduce muscle contraction—which is all a cramp is anyway, an uncontrolled contraction. Therefore stretching often is recommended especially if you know you are a cramper.

“I swallow an electrolyte pill and my cramping stops.” This is a comment we hear often, and although we cannot explain this physiologically, the more important message is that you have found something that works for you. We cannot stress how important this is! All the science in the world can point to something, but if what you are doing works for you, then you are better to stick with that technique. We invest so much time and energy (i.e. blood, sweat and tears!) into our training, and if you know that taking some supplement—providing it is legal, of course—will prevent a cramp during your marathon, then by all means you must take it.

But wait. . .I am not a cramper, how can I reduce my chances?

Fatigue appears to be a common factor in cramps, and so preventing fatigue or delaying its onset is crucial. However, we can hear you all the way in Chicago and Cape Town saying, “Great! if only it were that easy. . why didn’t you just say so?”

First of all, “Out running” your training could be a likely contributor to cramps. By this we mean that you know good and well that you have done the training for a 3:30 marathon, but in spite of that you decide you are going to go out at 2:55 pace. You feel great for about two hours, and then all hell breaks loose, the wheels fall off, and you are left in a crumpled heap with 5-10 km to go. Therefore we would suggest trying to race closer to your abilities in an effort to reduce the amount of fatigue you acquire during the event.

Second, progressive training is something else that we can all practice that will likely help reduce the chances that we cramp. Don’t go from “zero to hero” and make large increases in your training from week to week. As many of you might already know, rest is just as important as all the intensity and distance work you do, because it is during rest periods that your body actually makes the adaptations. Therefore small and incremental increases in training with appropriate rest will provide your body with the maximum time to make the necessary adaptations, and it is those adaptations that will delay the onset of fatigue.

Physiology is a complicated topic, and the available evidence on cramps is sparse. To really advance our knowledge we need solid lab studies that help us identify exactly what is going on and why the cramps occur. In fact, just creating a reliable and reproducible lab protocol would be a major step in identifying what causes the cramps in the first place. However cramps tend to be unpredictable in most people, and even in the known “crampers” it is difficult to bring them in the lab and make them cramp 100% of the time. So the beat of science marches on, and we can only hope that even as you read this, some PhD student out there is hard at work dreaming up a thesis that investigates this issue and tries to advance our knowledge!