title: Unusual causes of stiffness in two hockey players.
abstract: OBJECTIVE
  To describe two cases of competitive hockey players whose performance was impaired by generalized painless muscle stiffness. They were each found to have a separate type of myotonia.
  
  
  METHODS
  The first hockey player experienced stiffness only when initiating activity after a period of inactivity. He had a family history of muscle stiffness, grip myotonia clinically, and electrophysiologic findings of myotonic discharges. He had myotonia congenita. The stiffness in the second case was episodic and occurred during bouts of intense physical activity. The legs, arms, and neck were affected. Myotonia fluctuans was the probable diagnosis. Both cases responded well to Mexiletine.
  
  
  CONCLUSIONS
  The etiology, classification, and clinical presentation of myotonia are discussed.
  
  
  CONCLUSIONS
  Because of the musculoskeletal nature of our practice, sport medicine clinicians should be aware of myotonic disorders so they can be recognized and appropriately treated.
authors.affiliation: Division of Physical Medicine and Rehabilitation, Faculty of Medicine, University of Alberta, Edmonton, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Burnham
mesh_terms: D000293:Adolescent; D000328:Adult; D006688:Hockey / Q000293:injuries*; D006801:Humans; D008297:Male; D008801:Mexiletine / Q000627:therapeutic use; D009222:Myotonia / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology; D009224:Myotonia Congenita / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology
chemical_list: D008801:Mexiletine