title: Dynamic sagittal plane trunk control during anterior cruciate ligament injury.
abstract: BACKGROUND
  Recent studies have demonstrated that trunk control likely plays a role in anterior cruciate ligament (ACL) injury. Yet, the majority of ACL research remains focused on the lower limb, with limited information on the trunk position at the time of injury.
  
  
  OBJECTIVE
  Athletes experiencing a noncontact ACL injury after a 1-legged landing position their center of mass (COM) more posterior from the base of support (BOS) at initial ground contact in comparison with uninjured athletes. The distance from the COM to the BOS (COM_BOS) is larger in female, as compared with male, athletes during 1-legged landing.
  
  
  METHODS
  Case control study; Level of evidence, 3.
  
  
  METHODS
  Movie captures of 20 athletes performing a 1-legged landing maneuver resulting in a torn ACL were compared with matched (for gender, sport, and activity just before landing) movie captures of 20 athletes performing a similar maneuver that did not result in an ACL disruption (controls). The COM_BOS, trunk(G) angle, and limb(G) angle (both relative to the gravity vector) were measured in the sagittal plane at initial ground-foot contact. A 2-way ANOVA (injury status × gender) was used to examine the hypotheses.
  
  
  RESULTS
  There was a significant difference in all 3 measures based on injury status but not on gender. The COM_BOS, normalized by femur length, and limb(G) angle were greater (Δ = 0.9, P < .001 and Δ = 16°, P = .004, respectively), and the trunk(G) angle was smaller (Δ = 12°, P = .016) in the participants who sustained an ACL injury as compared with controls. The average COM was calculated as 38 cm more posterior relative to the BOS in the participants who sustained an ACL injury as compared with controls.
  
  
  CONCLUSIONS
  Landing with the COM far posterior to the BOS may be a risk factor for noncontact ACL injury and potentially can be addressed in prevention programs.
authors.affiliation: National Institutes of Health, Bethesda, MD, USA.
authors.forename: Frances T
authors.initials: FT
authors.lastname: Sheehan
authors.forename: William H
authors.initials: WH
authors.lastname: Sipprell
authors.forename: Barry P
authors.initials: BP
authors.lastname: Boden
mesh_terms: D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000209:etiology* / Q000517:prevention & control; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000209:etiology* / Q000517:prevention & control; D007866:Leg / Q000502:physiology; D008297:Male; D011187:Posture / Q000502:physiology*; D012737:Sex Factors; D060726:Torso / Q000502:physiology*; D014741:Video Recording