title: Hamstring Strength Asymmetry at 3 Years After Anterior Cruciate Ligament Reconstruction Alters Knee Mechanics During Gait and Jogging.
abstract: BACKGROUND
  Anterior cruciate ligament reconstruction (ACLR) using a hamstring tendon autograft often results in hamstring muscle strength asymmetry. However, the effect of hamstring muscle strength asymmetry on knee mechanics has not been reported.
  
  
  OBJECTIVE
  Participants with hamstring strength asymmetry would demonstrate altered involved limb knee mechanics during walking and jogging compared with those with more symmetric hamstring strength at least 2 years after ACLR with a hamstring tendon autograft.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  There were a total of 45 participants at least 2 years after ACLR (22 male, 23 female; mean time after ACLR, 34.6 months). A limb symmetry index (LSI) was calculated for isometric hamstring strength to subdivide the sample into symmetric hamstring (SH) (LSI ≥90%; n = 18) and asymmetric hamstring (AH) (LSI <85%; n = 18) groups. Involved knee kinematic and kinetic data were collected using 3-dimensional motion analysis during gait and jogging. Peak sagittal-, frontal-, and transverse-plane knee angles and sagittal-plane knee moments and knee powers were calculated. Independent-samples t tests and analyses of covariance were used to compare involved knee kinematic and kinetic variables between the groups.
  
  
  RESULTS
  There were no differences in sagittal- and frontal-plane knee angles between the groups ( P > .05 for all). The AH group demonstrated decreased tibial internal rotation during weight acceptance during gait ( P = .01) and increased tibial external rotation during jogging at initial contact ( P = .03) and during weight acceptance ( P = .02) compared with the SH group. In addition, the AH group demonstrated decreased peak negative knee power during midstance ( P = .01) during gait compared with the SH group, after controlling for gait speed, which differed between groups.
  
  
  CONCLUSIONS
  Participants with hamstring strength asymmetry showed altered involved knee mechanics in the sagittal plane during gait and in the transverse plane during gait and jogging compared with those with more symmetric hamstring strength.
  
  
  CONCLUSIONS
  Hamstring strength asymmetry is common at 3 years after ACLR with a hamstring tendon autograft and affects involved knee mechanics during gait and jogging. Additional research is warranted to further investigate the longitudinal effect of these alterations on knee function and joint health after ACLR.
authors: The Ohio State University College of Medicine, Columbus, Ohio, USA.
authors: Matthew N
authors: MN
authors: Abourezk
authors: School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA.|OSU Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors: Matthew P
authors: MP
authors: Ithurburn
authors: School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA.
authors: Michael P
authors: MP
authors: McNally
authors: Department of Physical Therapy, University of Delaware, Newark, Delaware, USA.
authors: Louise M
authors: LM
authors: Thoma
authors: OSU Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Sports Medicine Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors: Matthew S
authors: MS
authors: Briggs
authors: Sports Medicine Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Biomechanics Laboratories and Sports Medicine Center, Departments of Orthopedic Surgery, Physical Medicine and Rehabilitation, and Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA.
authors: Timothy E
authors: TE
authors: Hewett
authors: Department of Orthopaedics, Cleveland Clinic Sports Health Center, Cleveland, Ohio, USA.
authors: Kurt P
authors: KP
authors: Spindler
authors: OSU Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Sports Medicine Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.
authors: Christopher C
authors: CC
authors: Kaeding
authors: School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA.|OSU Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.|Division of Physical Therapy, School of Health and Rehabilitation Sciences, The Ohio State University, Columbus, Ohio, USA.
authors: Laura C
authors: LC
authors: Schmitt
mesh_terms: D000293:Adolescent; D000328:Adult; D059549:Anterior Cruciate Ligament Reconstruction; D001265:Athletic Injuries / Q000601:surgery; D064592:Autografts / Q000637:transplantation; D001696:Biomechanical Phenomena; D002648:Child; D005260:Female; D005684:Gait; D000070633:Hamstring Muscles / Q000502:physiology*; D000070632:Hamstring Tendons; D006801:Humans; D007590:Jogging; D007719:Knee Joint / Q000601:surgery; D008297:Male; D053580:Muscle Strength; D009820:Ohio; D013997:Time Factors; D016138:Walking; D055815:Young Adult
keywords: ACL; biomechanics; gait analysis; motion analysis