We describe the case of a previously well 55-year-old man who presented to the accident and emergency department with marked swelling of both forearms 6 days after being pulled at speed on a 'fun ride' by a speedboat whilst holding on to a rubber dinghy. Immediately after the event he had marked weakness of both arms lasting 2 days and this was followed by swelling of his forearms. The patient had also noticed a darkening of his urine during this period. On examination there was marked pitting oedema of both forearms. Neurovascular examination of both arms was normal. Laboratory investigations revealed a grossly elevated serum creatinine kinase at 4969 IU/l, with normal urea and electrolyte levels. Urine dipstick testing was also normal at the time of presentation. The patient was discharged home and made an uneventful recovery. We describe the pathophysiology of exercise-induced rhabdomyolysis and discuss its clinical presentation and management.