title: The association between lower extremity energy absorption and biomechanical factors related to anterior cruciate ligament injury.
abstract: BACKGROUND
  Greater total energy absorption by the lower extremity musculature during landing may reduce stresses placed on capsuloligamentous tissues with differences in joint contributions to energy absorption potentially affecting anterior cruciate ligament injury risk. However, the relationships between energy absorption and prospectively identified biomechanical factors associated with non-contact anterior cruciate ligament injury have yet to be demonstrated.
  
  
  METHODS
  Sagittal plane total, hip, knee and ankle energy absorption, and peak vertical ground reaction force, anterior tibial shear force, knee flexion and knee valgus angles, and internal hip extension and knee varus moments were measured in 27 individuals (14 females, 13 males) performing double leg jump landings. Correlation coefficients assessed the relationships between energy absorption during three time intervals (initial impact phase, terminal phase, and total landing) and biomechanical factors related to anterior cruciate ligament injury.
  
  
  RESULTS
  More favorable values of biomechanical factors related to non-contact anterior cruciate ligament injury were associated with: 1) Lesser total (R(2)=0.178-0.558), hip (R(2)=0.229-0.651) and ankle (R(2)=0.280), but greater knee (R(2)=0.147) energy absorption during the initial impact phase; 2) Greater total (R(2)=0.170-0.845), hip (R(2)=0.599), knee (R(2)=0.236-0.834), and ankle (R(2)=0.276) energy absorption during the terminal phase of landing; and 3) Greater knee (R(2)=0.158-0.709), but lesser hip (R(2)=0.309) and ankle (R(2)=0.210-0.319) energy absorption during the total landing period.
  
  
  CONCLUSIONS
  These results suggest that biomechanical factors related to anterior cruciate ligament injury are influenced by both the magnitude and timing of lower extremity energy absorption during landing.
authors.affiliation: Neuromuscular Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA. norcross@email.unc.edu
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: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D006615:Hip / Q000503:physiopathology; D006801:Humans; D007717:Knee / Q000502:physiology / Q000503:physiopathology*; D007718:Knee Injuries / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D035002:Lower Extremity; D008297:Male; D009068:Movement