title: Concurrent assessments of lower limb loading patterns, mechanical muscle strength and functional performance in ACL-patients--a cross-sectional study.
abstract: BACKGROUND
  Full recovery in muscle strength and functional performance may not be achieved after ACL-injury.
  
  
  OBJECTIVE
  The aim of this study is to investigate loading patterns during jumping, muscle function and functional performance in ACL-reconstructed patients and to investigate the origin of between-limb asymmetry by means of a 3-dimensional movement analysis. Design is cross-sectional.
  
  
  METHODS
  23 ACL-reconstructed men (27.2±7.5 years, BMI: 25.4±3.2) 27±7 month post-surgery and 25 matched controls (27.2±5.4 years, BMI: 24.1±1.8) were included. Participants performed (i) bilateral and (ii) unilateral counter movement jumps (CMJ). A 3-D movement analysis was performed by a six-camera Vicon MX-system. Subsequently, jump height (JH), knee joint range of motion (ROM), peak and mean sagittal knee moments were analyzed (iii) one-leg maximal jump for distance was performed, and (iv) maximal unilateral isometric knee extensor and flexor strength (MVC) were measured using stabilized dynamometry.
  
  
  RESULTS
  No in-between group differences in age or BMI were observed. CMJ: Between-limb asymmetry ratios for ROM differed (p<0.01) between patients and controls in both types of CMJ (96.1% vs. 102.6% and 87.0% vs. 99.9% in bilateral and single-leg CMJs, respectively). Jump for distance: Patients demonstrated greater (p<0.01) asymmetry for jump length (92.9% vs. 98.6%). MVC: Asymmetry in hamstring MVC was greater (p<0.001) for patients than controls (77.4% vs. 101.3%).
  
  
  CONCLUSIONS
  ACL-patients showed reduced function of the operated leg~2 years post ACL-reconstruction, especially for hamstring MVC. Hamstrings are important protagonists to the ACL, thus representing a potential risk factor for secondary ACL-rupture and/or osteoarthritis.
authors.affiliation: Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Denmark. Electronic address: ahlarsen@health.sdu.dk.
authors.forename: A
authors.initials: A
authors.lastname: Holsgaard-Larsen
authors.affiliation: Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Jensen
authors.affiliation: Orthopaedic Research Unit, Department of Orthopaedics and Traumatology, Odense University Hospital, Institute of Clinical Research, University of Southern Denmark, Denmark.
authors.forename: N H M
authors.initials: NH
authors.lastname: Mortensen
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, Muscle Research Cluster (SMRC), University of Southern Denmark, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Aagaard
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D016022:Case-Control Studies; D003198:Computer Simulation; D003430:Cross-Sectional Studies; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D007537:Isometric Contraction / Q000502:physiology; D007719:Knee Joint / Q000503:physiopathology; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D009068:Movement / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016059:Range of Motion, Articular / Q000502:physiology
keywords: ACL reconstruction; Asymmetry; Functional performance; Muscle strength