Photo: iStock.com/olegbreslavtsev

Cramp affects almost every endurance athlete at some point or other. It can be caused by a number of factors, which can be narrowed down as follows.

Often, a change in muscular load or simple overexertion is the main cause of cramp. During a triathlon, for example, cramp can occur both after the transition from the horizontal swimming position to the bike stage, and following the transition to the run stage, because the type of exertion changes completely within seconds and your muscles must first readapt to this.

In general, however, it is hard to find the cause of cramp during endurance sport – it is a puzzle consisting of several pieces. Here is an overview of the main causes:

Unusual movements: we have all experienced this; we are lying in bed and move in a certain way – stretching our toes, for example – and suddenly our calf cramps. Cramp often occurs when we move in an unusual way. If this movement is preceded by intense sporting activity, the risk of cramp increases.

Overexertion: when a muscle cramps, it is unable to cope with the exertion at that particular moment. In sport, this usually occurs when running too fast during a race and your muscle isn’t used to this level of intensity, for example. Or when it has to withstand explosive movements and hasn’t had chance to gradually warm up.

Fatigue: it is rare for cramp to occur the minute you start exercising (except for explosive or completely unusual movements) – it usually appears when your reserves are exhausted and your muscles are fatigued. This may be due to a lack of or incorrect training, or simply the length of time spent exercising, if this is longer than usual. Repetitive exertion such as cycling can also increase the risk of cramp.

Dehydration: a lack of fluids can also cause cramp, especially when combined with hot weather and high-intensity exertion. The electrolytes and mineral salts excreted during heavy perspiration must be replaced when exercising for long periods (e.g. using sports drinks, bouillon and/or salt supplements).

The cause of cramp isn’t always obvious, because medication, alcohol, lack of sleep and stress can also play a role. And at some point during a race, it can even affect athletes who normally never suffer from cramp.

And what if cramp occurs?

If cramp occurs while training or competing, you should immediately slow down and try to relax. At the same time, change the way you move, for example by sliding further forwards or backwards or standing up on your bike. When running, it helps to gently stretch the affected muscle. Icing or massaging the area can also be beneficial, if possible. You should also boost your energy and fluid intake.

Finally, a few words about the much-debated magnesium as a possible cause of cramp: for anyone without a magnesium deficiency (and that includes most of us), taking magnesium supplements will not help. The magnesium myth can be traced back to a single case study that is now over 30 years old – and has wrongly persisted until today, thanks mainly to clever marketing specialists in the sports sector.

According to the latest studies, it currently seems more beneficial to drink pickle juice and/or vinegar water for cramp. Presumably, its acidic taste in your mouth restricts the activity of impulse-generating neurons, thereby relieving cramp. As a result, new products that claim to prevent cramp have entered the market.