title: Quadriceps Function and Gait Kinetics after Anterior Cruciate Ligament Reconstruction.
abstract: Chronic quadriceps dysfunction has been implicated as a contributor to knee osteoarthritis (OA) development after anterior cruciate ligament reconstruction (ACLR). This dysfunction potentially leads to impulsive/high-rate loading during gait, thus accelerating cartilage degradation. The purpose of this study was to examine relationships between several indices of quadriceps function and gait biomechanics linked to knee OA development in individuals with ACLR.
  
  
  
  Gait biomechanics and quadriceps function were assessed in 39 individuals with ACLR. Indices of quadriceps function included isometric peak torque and rate of torque development (RTD), isokinetic peak torque and power, and the central activation ratio. Gait biomechanics included the peak vertical ground reaction force and loading rate, and the heel strike transient (HST) magnitude and loading rate.
  
  
  
  Isometric peak torque was not associated with any of the gait biomechanical variables. However, greater RTD was associated with lesser peak vertical ground reaction force linear (r = -0.490, P = 0.003) and instantaneous (r = -0.352, P = 0.031) loading rates, as well as a lesser HST magnitude (r = -0.312, P = 0.049) and instantaneous loading rate (r = -0.355, P = 0.029). Greater central activation ratio was associated with greater HST instantaneous (r = 0.311, P = 0.050) and linear (r = 0.328, P = 0.033) loading rates. Isokinetic peak torque and power were not associated with any of the biomechanical variables.
  
  
  
  Poor quadriceps function, especially RTD, is associated with gait kinetics linked to cartilage degradation in individuals with ACLR. These results highlight the likely role of chronic quadriceps dysfunction in OA development after ACLR and the need to emphasize improving quadriceps function as a primary rehabilitation goal.
authors.affiliation: 1Neuromuscular Research Laboratory, University of North Carolina at Chapel Hill, Chapel Hill, NC; 2Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC; 3Program in Human Movement Science, University of North Carolina at Chapel Hill, Chapel Hill, NC; and 4Department of Kinesiology, California State University, Fullerton, CA.
authors.forename: J Troy
authors.initials: JT
authors.lastname: Blackburn
authors.forename: Brian
authors.initials: B
authors.lastname: Pietrosimone
authors.forename: Matt S
authors.initials: MS
authors.lastname: Harkey
authors.forename: Brittney A
authors.initials: BA
authors.lastname: Luc
authors.forename: Derek N
authors.initials: DN
authors.lastname: Pamukoff
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena; D003430:Cross-Sectional Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D053580:Muscle Strength; D020370:Osteoarthritis, Knee / Q000503:physiopathology*; D052097:Quadriceps Muscle / Q000503:physiopathology*; D019415:Torque; D055815:Young Adult