Factors associated with a self-reported history of exercise-associated muscle cramps in Ironman triathletes: a case-control study

Clin J Sport Med. 2011 May;21(3):204-10. doi: 10.1097/JSM.0b013e31820bcbfd.


Objective: Exercise-associated muscle cramping (EAMC) is a common medical condition in endurance athletes. The exact cause of and risk factors for EAMC are still being investigated. The main objective of this study was to investigate factors that are associated with a self-reported history of EAMC in Ironman triathletes.

Design: Case-control study.

Setting: Field study at an international Ironman Triathlon.

Participants: Triathletes participating in an Ironman Triathlon were recruited as subjects.

Assessment of risk factors: A previously validated prerace questionnaire was completed by 433 subjects who were divided into subjects who reported a history of EAMC (EAMC group = 216) and those who no reported history of EAMC (CON group = 217).

Main outcome measures: Training, anthropometric, injury and performance, and other variables that were related to the history of EAMC.

Results: Compared with the CON group, triathletes in the EAMC group were significantly taller and heavier, had faster Ironman race times despite being of similar caliber (past personal best times), and predicted and achieved a faster overall time during the Ironman Triathlon. There was an association among a positive family history for EAMC, a history of tendon and/or ligament injuries, and a self-reported history of EAMC.

Conclusions: There is evidence from this study that a history of EAMC is associated with (1) exercising at a higher intensity during a race that may result in premature muscle fatigue, (2) an inherited risk (positive family history), and (3) a history of tendon and/or ligament injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Athletes*
  • Athletic Injuries / etiology*
  • Athletic Injuries / prevention & control
  • Body Height / physiology
  • Body Weight / physiology
  • Case-Control Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Muscle Cramp / epidemiology*
  • Muscle Cramp / etiology
  • Muscle Cramp / prevention & control
  • Muscle Fatigue / physiology
  • Muscle Stretching Exercises
  • Physical Endurance / physiology
  • Risk Factors
  • Running / physiology