Ask an expert

12h ago


I am beginning to cycle quite seriously at the moment, but I quite frequently suffer from major cramping. What is the cause of this cramping?

Answer 421 views

01 Jan 0001

Hi James

There are so many myths about cramping that a lot of what I have to say may come as a surprise to you. To start with, the bottom line is that cramping is not caused by mineral deficiency and so supplements do not help prevent them (at least not directly, although they may contribute indirectly, as I'll explain). A few years ago, a big study on 2 Oceans and Comrades runners found that when you compare the magnesium, sodium and calcium levels of runners with cramp with runners without cramp, there's no difference - that means that people cramp even though their mineral levels are exactly the same. So, this myth has come about based on very early studies in mines etc. and a lot of it has been driven by sports drink companies who want to market the products as a cure for cramp.The bottom line is that you are cramping even though your vitamins and mineral levels are normal.

So, then, what causes cramp? Without getting too technical, cramping is caused by a reflex stimulation of the muscle by the central nervous system - the muscle is constantly controlled by nerves and reflexes, and there's good evidence to show that a cramp occurs when the reflex control of muscle breaks down and the muscle is stimulated excessively. Exactly what causes this is unknown although it is known that fatigue is a major contributor - that's why people cramp late in races, more often they also cramp in the heat (it causes more fatigue), or when it's windy, a hilly course, or a tough race. It also explains why you cramp in the muscles you use only for cycling and not in the arms, for example - the muscles become fatigues, and this somehow interferes with the nervous system and the control of the muscle, causing them to cramp.

So, the immediate treatment for a cramp is to stop and stretch the muscle very well - tests have shown that as soon as you do this, the reflex control of the muscle is restored, and this stops the cramp immediately. In terms of prevention, stretching regularly to improve your overall flexibility may help, stretching before the ride may also help, and then stretching during the ride is also a good idea - you can do this on the downhills, by just unclipping a leg, or bending down - you can get creative.

Then the other factor that helps prevent cramp is muscle strength. It's not a co-incidence that the people who cramp are often racing hard, or pushing harder than their training has allowed them. So, the training is very important, and getting to maximum fitness is vital. This would include doing rides in a very heavy gear, where you are deliberating fatiguing the muscles, making them stronger, so that in a race, they are able to handle it when you are tired near the end. I would include one ride per week, where you go over a gently rolling terrain in a big gear and really push your legs hard - this won't feel that hard on the breathing or heart, but your legs certainly will feel it. Hill training also helps. BY improving the muscle strength, you will delay muscle fatigue, and then hopefully the cramp won't occur.

So, these are the natural, more scientifically ways of preventing cramp.

I hope they work for you.
Voting Booth
Have you entered our Health of the Nation survey?
33% - 9375 votes
67% - 19420 votes