title: Mechanisms and situations of anterior cruciate ligament injuries in professional male soccer players: a YouTube-based video analysis.
abstract: BACKGROUND
  Soccer is considered the most popular sport in the world concerning both audience and athlete participation, and the incidence of ACL injury in this sport is high. The understanding of injury situations and mechanisms could be useful as substratum for preventive actions.
  
  
  OBJECTIVE
  To conduct a video analysis evaluating the situations and mechanisms of ACL injury in a homogeneous population of professional male soccer players, through a search entirely performed on the YouTube.com Web site focusing on the most recent years.
  
  
  METHODS
  A video analysis was conducted obtaining videos of ACL injury in professional male soccer players from the Web site YouTube. Details regarding injured players, events and situations were obtained. The mechanism of injury was defined on the basis of the action, duel type, contact or non-contact injury, and on the hip, knee and foot position.
  
  
  RESULTS
  Thirty-four videos were analyzed, mostly from the 2014-2015 season. Injuries occurred mostly in the first 9 min of the match (26%), in the penalty area (32%) or near the side-lines (44%), and in non-rainy conditions (97%). Non-contact injuries occurred in 44% of cases, while indirect injuries occurred in 65%, mostly during pressing, dribbling or tackling. The most recurrent mechanism was with an abducted and flexed hip, with knee at first degrees of flexion and under valgus stress.
  
  
  CONCLUSIONS
  Through a YouTube-based video analysis, it was possible to delineate recurrent temporal, spatial and mechanical characteristics of ACL injury in male professional soccer players.
  
  
  METHODS
  Level IV, case series.
authors.affiliation: Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, Palermo, Italy. alberto.grassi3@studio.unibo.it.|Laboratorio di Biomeccanica ed Innovazione Teconolgica, Istituto Ortopedico Rizzoli, Bologna, Italy. alberto.grassi3@studio.unibo.it.
authors.forename: Alberto
authors.initials: A
authors.lastname: Grassi
authors.affiliation: Duke Medical School, Durham, NC, USA.
authors.forename: Stephen Paul
authors.initials: SP
authors.lastname: Smiley
authors.affiliation: Laboratorio di Biomeccanica ed Innovazione Teconolgica, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Roberti di Sarsina
authors.affiliation: Laboratorio di Biomeccanica ed Innovazione Teconolgica, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Signorelli
authors.affiliation: Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, Palermo, Italy.|Laboratorio di Biomeccanica ed Innovazione Teconolgica, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Giulio Maria
authors.initials: GM
authors.lastname: Marcheggiani Muccioli
authors.affiliation: Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, Palermo, Italy.
authors.forename: Alice
authors.initials: A
authors.lastname: Bondi
authors.affiliation: Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, Palermo, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Romagnoli
authors.affiliation: Facoltà di Scienze Motorie, Università di Bologna, Bologna, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Agostini
authors.affiliation: Dipartimento Rizzoli Sicilia, Istituto Ortopedico Rizzoli, Bagheria, Palermo, Italy.|Laboratorio di Biomeccanica ed Innovazione Teconolgica, Istituto Ortopedico Rizzoli, Bologna, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Zaffagnini
mesh_terms: D000070598:Anterior Cruciate Ligament Injuries / Q000209:etiology*; D006801:Humans; D008297:Male; D004856:Postural Balance / Q000502:physiology; D012916:Soccer / Q000293:injuries*; D014741:Video Recording
keywords: Anterior cruciate ligament; Injury; Soccer; Video analysis; YouTube.com