The case is reported of bilateral rhabdomyolysis of the long head of the triceps following intensive exercise in a 30 year old male weightlifter. The diagnosis was based on myalgias localised to one muscle and raised levels of muscle enzymes. Magnetic resonance imaging helped to locate the site and extent of muscular involvement. Treatment consisted of complete rest and adequate intravenous perfusion to allow clearance of the clinical and biological abnormalities and prevent renal involvement.