Many athletes suffer from cramps, but despite the high prevalence of exercise-associated muscle cramping (EAMC), the mechanisms are not fully understood.

This study looked at 210 triathletes competing in an Ironman triathlon and monitored their minerals intakes and losses, as well as hydration status, to search for any relationships with cramping.Prior to racing, subjects completed a detailed validated questionnaire and blood samples were taken for serum electrolytes before and after racing. Pre and post weights were analysed to account for fluid losses.  43 triathletes reported cramping group and were compared with the 166 who did not.

There were no significant differences between groups in any pre-race–post-race serum electrolyte concentrations or body weight changes, surprisingly showing that hydration status didn’t correlate with cramping. Cramping was however associated with faster race times and a prior history of cramping.

As cramping is associated with intensity of exercise, it can only be concluded that the main way to try and combat cramping is to increase fitness and the experience of high-intensity training to mimic race conditions. Hydration and proper fuelling should be closely monitored to support the necessary fitness gains.

Many athletes suffer from reduced magnesium levels when upping their training intensity, while heavy losses have correlated with overtraining type symptoms. A good mineral intake; possibly even supplementing, will act as an insurance policy against fatigue:

Schwellnus MP, Drew N, Collins M. (2011) Increased running speed and previous cramps rather than dehydration or serum sodium changes predict exercise-associated muscle cramping: a prospective cohort study in 210 Ironman triathletes; Br J Sports Me; 45 (8): 650-6. Epub 2010 Dec 9.