Muscle Cramping During a 161-km Ultramarathon: Comparison of Characteristics of Those With and Without Cramping For 100 miles runners, runners were examined with and runners without muscle cramps. It showed around 14% of the runners had cramps and got about 53% almost cramps.Most cramps occurred in the calves (54%), quadriceps (44%) and Hamstring (33%).
In runners with cramps earlier convulsions and after the run higher CK values. The whole work can be found under https://www.sportsmedicine-open.com/content/2/1/8