title: Recurrence of Achilles tendon injuries in elite male football players is more common after early return to play: an 11-year follow-up of the UEFA Champions League injury study.
abstract: BACKGROUND
  There is limited information about Achilles tendon disorders in professional football.
  
  
  OBJECTIVE
  To investigate the incidence, injury circumstances, lay-off times and reinjury rates of Achilles tendon disorders in male professional football.
  
  
  METHODS
  A total of 27 clubs from 10 countries and 1743 players have been followed prospectively during 11 seasons between 2001 and 2012. The team medical staff recorded individual player exposure and time-loss injuries.
  
  
  RESULTS
  A total of 203 (2.5% of all injuries) Achilles tendon disorders were registered. A majority (96%) of the disorders were tendinopathies, and nine were partial or total ruptures. A higher injury rate was found during the preseason compared with the competitive season, 0.25 vs 0.18/1000 h (rate ratio (RR) 1.4, 95% CI 1.1 to 2.0; p=0.027). The mean lay-off time for Achilles tendinopathies was 23±37 (median=10, Q1=4 and Q3=24) days, while a rupture of the Achilles tendon, on average, caused 161±65 (median=169, Q1=110 and Q3=189) days of absence. Players with Achilles tendon disorders were significantly older than the rest of the cohort, with a mean age of 27.2±4 years vs 25.6±4.6 years (p<0.001). 27% of all Achilles tendinopathies were reinjuries. A higher reinjury risk was found after short recovery periods (31%) compared with longer recovery periods (13%) (RR 2.4, 95% CI 2.1 to 2.8; p<0.001).
  
  
  CONCLUSIONS
  Achilles tendon disorders account for 3.8% of the total lay-off time and are more common in older players. Recurrence is common after Achilles tendinopathies and the reinjury risk is higher after short recovery periods.
authors.affiliation: Division of Community Medicine, Department of Medical and Health Sciences, Linköping University, Linköping, Sweden.
authors.forename: Mariann
authors.initials: M
authors.lastname: Gajhede-Knudsen
authors.forename: Jan
authors.initials: J
authors.lastname: Ekstrand
authors.forename: Henrik
authors.initials: H
authors.lastname: Magnusson
authors.forename: Nicola
authors.initials: N
authors.lastname: Maffulli
mesh_terms: D000041:Absenteeism; D000125:Achilles Tendon / Q000293:injuries* / Q000502:physiology; D000328:Adult; D001265:Athletic Injuries / Q000453:epidemiology / Q000503:physiopathology; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D005060:Europe / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology; D012008:Recurrence; D012421:Rupture / Q000453:epidemiology / Q000503:physiopathology; D012916:Soccer / Q000293:injuries*; D052256:Tendinopathy / Q000453:epidemiology / Q000503:physiopathology; D013997:Time Factors
keywords: Achilles tendon; Elite performance; Epidemiology; Lower extremity injuries; Soccer