Exercise associated muscle cramps (EAMC) are generally spasmatic and involuntary contractions of skeletal muscles that occur during or immediately after exercise. They result in bulging or knotting of the muscle and usually occur in multi-joint muscle groups when contracting in a shortened position (i.e. quadriceps, hamstrings, calf).

Athletes have historically blamed electrolyte imbalance, nutrition or dehydration for their cramps … but we now know cramping is almost always triggered by hyperactive nerves pounding fatiguing muscles during exercise.  As muscles fatigue, motor neurons that induce contraction (or shortening) of the muscle fibers begin to fire uncontrollable into the muscle.  It’s this loss of neuromuscular control that triggers the onset of a cramp.