title: The Vertical Drop Jump Is a Poor Screening Test for ACL Injuries in Female Elite Soccer and Handball Players: A Prospective Cohort Study of 710 Athletes.
abstract: BACKGROUND
  The evidence linking knee kinematics and kinetics during a vertical drop jump (VDJ) to anterior cruciate ligament (ACL) injury risk is restricted to a single small sample. Still, the VDJ test continues to be advocated for clinical screening purposes.
  
  
  OBJECTIVE
  To test whether 5 selected kinematic and kinetic variables were associated with future ACL injuries in a large cohort of Norwegian female elite soccer and handball players. Furthermore, we wanted to assess whether the VDJ test can be recommended as a screening test to identify players with increased risk.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  Elite female soccer and handball players participated in preseason screening tests from 2007 through 2014. The tests included marker-based 3-dimensional motion analysis of a drop-jump landing. We followed a predefined statistical protocol in which we included the following candidate risk factors in 5 separate logistic regression analyses, with new ACL injury as the outcome: (1) knee valgus angle at initial contact, (2) peak knee abduction moment, (3) peak knee flexion angle, (4) peak vertical ground-reaction force, and (5) medial knee displacement.
  
  
  RESULTS
  A total of 782 players were tested (age, 21 ± 4 years; height, 170 ± 7 cm; body mass, 67 ± 8 kg), of which 710 were included in the analyses. We registered 42 new noncontact ACL injuries, including 12 in previously ACL-injured players. Previous ACL injury (relative risk, 3.8; 95% CI, 2.1-7.1) and medial knee displacement (odds ratio, 1.40; 95% CI, 1.12-1.74 per 1-SD change) were associated with increased risk for injury. However, among the 643 players without previous injury, we found no association with medial knee displacement. A receiver operating characteristic curve analysis of medial knee displacement showed an area under the curve of 0.6, indicating a poor-to-failed combined sensitivity and specificity of the test, even when including previously injured players.
  
  
  CONCLUSIONS
  Of the 5 risk factors considered, medial knee displacement was the only factor associated with increased risk for ACL. However, receiver operating characteristic curve analysis indicated a poor combined sensitivity and specificity when medial knee displacement was used as a screening test for predicting ACL injury. For players with no previous injury, none of the VDJ variables were associated with increased injury risk.
  
  
  CONCLUSIONS
  VDJ tests cannot predict ACL injuries in female elite soccer and handball players.
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway tron.krosshaug@nih.no.
authors: Tron
authors: T
authors: Krosshaug
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Kathrin
authors: K
authors: Steffen
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Eirik
authors: E
authors: Kristianslund
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Agnethe
authors: A
authors: Nilstad
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Kam-Ming
authors: KM
authors: Mok
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Grethe
authors: G
authors: Myklebust
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Thor Einar
authors: TE
authors: Andersen
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Ingar
authors: I
authors: Holme
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Lars
authors: L
authors: Engebretsen
authors: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway.
authors: Roald
authors: R
authors: Bahr
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D056352:Athletes; D001265:Athletic Injuries / Q000175:diagnosis*; D015331:Cohort Studies; D005080:Exercise Test; D005260:Female; D006801:Humans; D008403:Mass Screening; D018570:Risk Assessment; D055815:Young Adult
keywords: anterior cruciate ligament; biomechanics; female; football; handball; screening; soccer; vertical drop jump