title: Trunk and hip biomechanics influence anterior cruciate loading mechanisms in physically active participants.
abstract: BACKGROUND
  Excessive trunk motion and deficits in neuromuscular control (NMC) of the lumbopelvic hip complex are risk factors for anterior cruciate ligament (ACL) injury. However, the relationship between trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads during a sidestep cutting task has not been examined.
  
  
  OBJECTIVE
  To determine if there is an association between multiplanar trunk motion, NMC of the lumbopelvic hip complex, and triplanar knee loads with ACL injury during a sidestep cutting task.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  The hip and knee biomechanics and trunk motion of 30 participants (15 male, 15 female) were analyzed during a sidestep cutting task using an optoelectric camera system interfaced to a force plate. Trunk and lower extremity biomechanics were calculated from the kinematic and ground-reaction force data during the first 50% of the stance time during the cutting task. Pearson product moment correlation coefficients were calculated between trunk and lower extremity biomechanics. Multiple linear regression analyses were carried out to determine the amount of variance in triplanar knee loading explained by trunk motion and hip moments.
  
  
  RESULTS
  A greater internal knee varus moment (mean, 0.11 ± 0.12 N·m/kg*m) was associated with less transverse-plane trunk rotation away from the stance limb (mean, 20.25° ± 4.42°; r = -0.46, P = .011) and a greater internal hip adduction moment (mean, 0.33 ± 0.25 N·m/kg*m; r = 0.83, P < .05). A greater internal knee external rotation moment (mean, 0.11 ± 0.08 N·m/kg*m) was associated with a greater forward trunk flexion (mean, 7.62° ± 5.28°; r = 0.42, P = .020) and a greater hip internal rotation moment (mean, 0.15 ± 0.16 N·m/kg*m; r = 0.59, P = .001). Trunk rotation and hip adduction moment explained 81% (P < .05) of the variance in knee varus moment. Trunk flexion and hip internal rotation moment explained 48% (P < .05) of the variance in knee external rotation moment.
  
  
  CONCLUSIONS
  Limited trunk rotation displacement toward the new direction of travel and hip adduction moment are associated with an increased internal knee varus moment, while a combined increase in trunk flexion displacement and hip internal rotation moment is associated with a higher internal knee external rotation moment.
  
  
  CONCLUSIONS
  Prevention interventions for ACL injury should encourage trunk rotation toward the new direction of travel and limit excessive trunk flexion while adjusting frontal- and transverse-plane hip NMC.
authors.affiliation: Barnett Frank, MA, ATC, Department of Exercise and Sport Science, The University of North Carolina at Chapel Hill, 209 Fetzer Hall, CB# 8700, Chapel Hill, NC 27599-8700. bsfrank@email.unc.edu.
authors.forename: Barnett
authors.initials: B
authors.lastname: Frank
authors.forename: David R
authors.initials: DR
authors.lastname: Bell
authors.forename: Marc F
authors.initials: MF
authors.lastname: Norcross
authors.forename: J Troy
authors.initials: JT
authors.lastname: Blackburn
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Goerger
authors.forename: Darin A
authors.initials: DA
authors.lastname: Padua
mesh_terms: D016118:Anterior Cruciate Ligament / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D012044:Regression Analysis; D060726:Torso / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology; D055815:Young Adult
keywords: anterior cruciate ligament; cutting task; hip biomechanics; joint; knee biomechanics; trunk motion