title: Risk factors of anterior cruciate ligament injury in football players: a systematic review of the literature.
abstract: BACKGROUND
  The ACL lesion represents one of the most dramatic injuries in a sportsman's career. There are many injury risk factors related to intrinsic, or non-modifiable, and extrinsic, or modifiable, factors. In literature at today current evidence suggests that ACL injury risk is multifactorial and involves biomechanical, anatomical, hormonal and neuromuscular factors.
  
  
  OBJECTIVE
  To perform a systematic review of the literature concerning the ACL injury risk factors in soccer.
  
  
  CONCLUSIONS
  The injury risk factors show a low level of evidence, further studies in the field are needed.
  
  
  METHODS
  Systematic review.
authors.affiliation: Department of Knee Orthopaedic and Sports Traumatology Unit, Humanitas Research Hospital, Rozzano, (MI), Italy; FC Internazionale Medical Staff, Milano, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Volpi
authors.affiliation: Qatar Orthopaedic and Sport Medicine Hospital, FIFA Center of Excellence, Doha, Qatar.
authors.forename: Gian Nicola
authors.initials: GN
authors.lastname: Bisciotti
authors.affiliation: Qatar Orthopaedic and Sport Medicine Hospital, FIFA Center of Excellence, Doha, Qatar.
authors.forename: Karim
authors.initials: K
authors.lastname: Chamari
authors.affiliation: Qatar Orthopaedic and Sport Medicine Hospital, FIFA Center of Excellence, Doha, Qatar.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Cena
authors.affiliation: Department of Knee Orthopaedic and Sports Traumatology Unit, Humanitas Research Hospital, Rozzano, (MI), Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Carimati
authors.affiliation: Department of Health Sciences (DISSAL), University of Genoa, Italy.
authors.forename: Nicola Luigi
authors.initials: NL
authors.lastname: Bragazzi
keywords: ACL; age; gender; genetic risk factors; training