title: Prediction of hamstring injury in professional soccer players by isokinetic measurements.
abstract: OBJECTIVE
  previous studies investigating the ability of isokinetic strength ratios to predict hamstring injuries in soccer players have reported conflicting results.
  
  
  OBJECTIVE
  to determine if isokinetic ratios are able to predict hamstring injury occurring during the season in professional soccer players.
  
  
  METHODS
  case-control study;
  
  
  METHODS
  3.
  
  
  METHODS
  from 2001 to 2011, 350 isokinetic tests were performed in 136 professional soccer players at the beginning of the soccer season. Fifty-seven players suffered hamstring injury during the season that followed the isokinetic tests. These players were compared with the 79 uninjured players. The bilateral concentric ratio (hamstring-to-hamstring), ipsilateral concentric ratio (hamstring-to-quadriceps), and mixed ratio (eccentric/concentric hamstring-to-quadriceps) were studied. The predictive ability of each ratio was established based on the likelihood ratio and post-test probability.
  
  
  RESULTS
  the mixed ratio (30 eccentric/240 concentric hamstring-to-quadriceps) <0.8, ipsilateral ratio (180 concentric hamstring-to-quadriceps) <0.47, and bilateral ratio (60 concentric hamstring-to-hamstring) <0.85 were the most predictive of hamstring injury. The ipsilateral ratio <0.47 allowed prediction of the severity of the hamstring injury, and was also influenced by the length of time since administration of the isokinetic tests.
  
  
  CONCLUSIONS
  isokinetic ratios are useful for predicting the likelihood of hamstring injury in professional soccer players during the competitive season.
authors.affiliation: Department of Pôle MPR, Hôpital Saint Jacques, CHU NANTES, France; INSERM, UMRS 791-LIOAD, Centre for osteo-articular and dental tissue engineering, groupe STEP, Nantes, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Dauty
authors.affiliation: Department of Pôle MPR, Hôpital Saint Jacques, CHU NANTES, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Menu
authors.affiliation: Department of Pôle MPR, Hôpital Saint Jacques, CHU NANTES, France.
authors.forename: Alban
authors.initials: A
authors.lastname: Fouasson-Chailloux
authors.affiliation: Department of Pôle MPR, Hôpital Saint Jacques, CHU NANTES, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Ferréol
authors.affiliation: Department of Pôle MPR, Hôpital Saint Jacques, CHU NANTES, France.
authors.forename: Charles
authors.initials: C
authors.lastname: Dubois
keywords: eccentric; muscle contraction; sports; strength