Q+A: I can’t explain my marathon calf cramps

Q I’m a 40-year-old male who’s been running for more than 10 years. Despite an eight-year gap between my second and third marathons, I still covered the distance without too many problems. However, after 22 miles of my fourth marathon (five months later) I suffered horrible cramps in both calves. I put this down to overtraining, so three weeks before my next marathon I eased down and did a lot of stretching. Despite this, I started cramping even sooner than before – at around 18 miles. I think I’m doing the right things – eating properly and taking isotonic drinks and plenty of water during and after runs – but curing the cramps seems beyond me. The problem is currently providing excellent ammunition to those who say I’m too old to run (but more importantly it hurts like crazy). What can I do?

A There are a number of possible causes for your type of problem, and I’ll begin with the most likely.

First, have you checked your shoes? Excessively worn shoes can promote an abnormal gait, which can lead to an increased load on the calf muscles. If the shoes are worn out on the inside, then you may be overpronating, in which case try an anti-pronating shoe and lots of calf stretching. If they show wear on the outside you may be a supinator, which means you do not absorb shock very well, and the shoes to look for should be more cushioned. Secondly, the layoff between the marathons may have caused (in conjunction with other problems you may not be aware of) your sciatic nerves to become tight and stiff – this sometimes results in some lower-back symptoms. Do you have any? If you do, and then go on to overload the nerves with low-grade, repetitive movements, they can become progressively traumatised, and the associated muscles can go into a protective spasm – in this case the calves. This may be the most likely cause if the nerve is stuck in the lower back as the problem is affecting both sides. If this seems to fit the bill, then stretching the sciatic nerve will help.

The third option is less common, and it relates to the muscle sheath (the ‘skin’ that surrounds the muscle). Occasionally the muscle can ‘outgrow’ the sheath, and when it becomes engorged with blood during exercise the sheath cannot stretch sufficiently to allow the muscle to function properly. This presents itself as cramp-like sensations which can stop you dead in your tracks. This is more difficult to treat conservatively, and although stretching and exercise can help, surgery is sometimes required.

Martin Haines, sports medicine consultant