[Effect of marathons on neuromuscular excitability; comparison of electromyographic and biochemical findings].

The aim of this paper is to study the neuromuscular excitability of a group of marathon runners and to see how it can be modified right after the marathon. Spontaneously appearing multiplets in EMG signal under ischaemia served as a test of the neuromuscular hyperexcitability. The percentage of positive tests is much higher than in the control population; as a rule, the effect of the marathon is to diminish the neuromuscular hyperexcitability. The concentrations of Ca, Mg and P in the plasma as well as the globular concentration of Mg have been determined several times, both before and after the marathon; no correlation has been found with the neuromuscular hyperexcitability.