title: Immersive virtual reality improves movement patterns in patients after ACL reconstruction: implications for enhanced criteria-based return-to-sport rehabilitation.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the influence of immersion in a virtual reality environment on knee biomechanics in patients after ACL reconstruction (ACLR). It was hypothesized that virtual reality techniques aimed to change attentional focus would influence altered knee flexion angle, knee extension moment and peak vertical ground reaction force (vGRF) in patients following ACLR.
  
  
  METHODS
  Twenty athletes following ACLR and 20 healthy controls (CTRL) performed a step-down task in both a non-virtual reality environment and a virtual reality environment displaying a pedestrian traffic scene. A motion analysis system and force plates were used to measure kinematics and kinetics during a step-down task to analyse each single-leg landing.
  
  
  RESULTS
  A significant main effect was found for environment for knee flexion excursion (P = n.s.). Significant interaction differences were found between environment and groups for vGRF (P = 0.004), knee moment (P < 0.001), knee angle at peak vGRF (P = 0.01) and knee flexion excursion (P = 0.03). There was larger effect of virtual reality environment on knee biomechanics in patients after ACLR compared with controls.
  
  
  CONCLUSIONS
  Patients after ACLR immersed in virtual reality environment demonstrated knee joint biomechanics that approximate those of CTRL. The results of this study indicate that a realistic virtual reality scenario may distract patients after ACLR from conscious motor control. Application of clinically available technology may aid in current rehabilitation programmes to target altered movement patterns after ACLR.
  
  
  METHODS
  Diagnostic study, Level III.
authors.affiliation: Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. a.gokeler@rug.nl.
authors.forename: Alli
authors.initials: A
authors.lastname: Gokeler
authors.affiliation: Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Marsha
authors.initials: M
authors.lastname: Bisschop
authors.affiliation: Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, Department of Pediatrics and Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Myer
authors.affiliation: Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.|School of Sport Studies, Hanze University Groningen, Groningen, The Netherlands.
authors.forename: Anne
authors.initials: A
authors.lastname: Benjaminse
authors.affiliation: Department of Oral and Maxillofacial Surgery, Center for Rehabilitation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Pieter U
authors.initials: PU
authors.lastname: Dijkstra
authors.affiliation: Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Helco G
authors.initials: HG
authors.lastname: van Keeken
authors.affiliation: Department of Orthopedic Surgery, Martini Hospital, Groningen, The Netherlands.
authors.forename: Jos J A M
authors.initials: JJ
authors.lastname: van Raay
authors.affiliation: Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Johannes G M
authors.initials: JG
authors.lastname: Burgerhof
authors.affiliation: Center for Human Movement Sciences, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Egbert
authors.initials: E
authors.lastname: Otten
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000534:rehabilitation / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000534:rehabilitation*; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D011182:Postoperative Care; D000068958:Return to Sport; D063367:Virtual Reality Exposure Therapy; D055815:Young Adult
keywords: Anterior cruciate ligament; External focus; Knee biomechanics; Motor learning