The Epidemiology Of Exercise Associated Muscle Cramps (EAMC) In Ironman Triathletes

Abstract

Despite anecdotal reports of a high prevalence of EAMC amongst triathletes, the epidemiology, including its associated factors, has not been well documented in these athletes. PURPOSE To investigate the prevalence of Exercise Associated Muscle Cramping (EAMC) in a group of Ironman triathletes. METHODS All 799 prospective participants of the South African Ironman Triathlon were sent a questionnaire to complete and return at registration (95.1% response rate). 68.5% of triathletes who responded to a section of the questionnaire detailing their cramping history reported a past history of EAMC and formed the ‘cramp-history’ (CH, n = 289) group. The remaining 31.5% reported no previous history of EAMC and formed the ‘non-cramping’ group (NC, n = 133). RESULTS A significantly greater number (p < 0.01) of the CH group reported cramping during running (37.1%) compared with swimming (28.9%) and cycling (15.6%), and during racing (46.1%) compared with training (18.8%). The majority of the CH group (56.5%) reported cramping in the final quarter of a race. The majority of the CH group rated their cramps as mild (77.5%), 17.4% as moderate and 3.6% as severe. 38.5% of the severe crampers had a family history of EAMC. The majority (58.4%) of the CH group associated subjective muscle fatigue with EAMC, although electrolyte imbalances (42.9%) and dehydration (42.6%) were also perceived to be associated with cramps. CONCLUSIONS There is a high prevalence of cramping history amongst Ironman triathletes that is often associated with running, racing and subjective muscle fatigue and occurs mostly in the last quarter of a race. A positive family history of cramping is associated with severe episodes of EAMC in some triathletes.