title: Shoulder pain in elite swimmers: primarily due to swim-volume-induced supraspinatus tendinopathy.
abstract: OBJECTIVE
  Shoulder pain in elite swimmers is common, and its pathogenesis is uncertain. HYPOTHESIS/STUDY DESIGN: The authors used a cross-sectional study design to test Jobe's hypothesis that repetitive forceful swimming leads to shoulder laxity, which in turn leads to impingement pain.
  
  
  METHODS
  Eighty young elite swimmers (13-25 years of age) completed questionnaires on their swimming training, pain and shoulder function. They were given a standardised clinical shoulder examination, and tested for glenohumeral joint laxity using a non-invasive electronic laxometer. 52/80 swimmers also attended for shoulder MRI.
  
  
  RESULTS
  73/80 (91%) swimmers reported shoulder pain. Most (84%) had a positive impingement sign, and 69% of those examined with MRI had supraspinatus tendinopathy. The impingement sign and MRI-determined supraspinatus tendinopathy correlated strongly (r(s)=0.49, p<0.00001). Increased tendon thickness correlated with supraspinatus tendinopathy (r(s)=0.37, p<0.01). Laxity correlated weakly with impingement pain (r(s)=0.23, p<0.05) and was not associated with supraspinatus tendinopathy (r(s)=0.14, p=0.32). The number of hours swum/week (r(s)=0.39, p<0.005) and weekly mileage (r(s)=0.34, p=0.01) both correlated significantly with supraspinatus tendinopathy. Swimming stroke preference did not.
  
  
  CONCLUSIONS
  These data indicate: (1) supraspinatus tendinopathy is the major cause of shoulder pain in elite swimmers; (2) this tendinopathy is induced by large amounts of swimming training; and (3) shoulder laxity per se has only a minimal association with shoulder impingement in elite swimmers. These findings are consistent with animal and tissue culture findings which support an alternate hypothesis: the intensity and duration of load to tendon fibres and cells cause tendinopathy, impingement and shoulder pain.
authors.affiliation: Orthopaedic Research Institute, University of New South Wales, St George Hospital, Australia.
authors.forename: Mya Lay
authors.initials: ML
authors.lastname: Sein
authors.forename: Judie
authors.initials: J
authors.lastname: Walton
authors.forename: James
authors.initials: J
authors.lastname: Linklater
authors.forename: Richard
authors.initials: R
authors.lastname: Appleyard
authors.forename: Brent
authors.initials: B
authors.lastname: Kirkbride
authors.forename: Donald
authors.initials: D
authors.lastname: Kuah
authors.forename: George A C
authors.initials: GA
authors.lastname: Murrell
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006811:Humerus / Q000293:injuries* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging; D008297:Male; D016059:Range of Motion, Articular; D019534:Shoulder Impingement Syndrome / Q000209:etiology* / Q000503:physiopathology; D020069:Shoulder Pain / Q000209:etiology* / Q000503:physiopathology; D013550:Swimming / Q000293:injuries* / Q000502:physiology; D052256:Tendinopathy / Q000209:etiology* / Q000503:physiopathology; D055815:Young Adult