title: Diminished sub-maximal quadriceps force control in anterior cruciate ligament reconstructed patients is related to quadriceps and hamstring muscle dyskinesia.
abstract: The aim of this study was to determine the effects of anterior cruciate ligament reconstruction (ACLR) on sub-maximal quadriceps force control with respect to quadriceps and hamstring muscle activity. Thirty ACLR individuals together with 30 healthy individuals participated. With real-time visual feedback of muscle force output and electromyographic electrodes attached to the quadriceps and hamstring muscles, subjects performed an isometric knee extension task where they increased and decreased their muscle force output at 0.128Hz within a range of 5-30% maximum voluntary capacity. The ACLR group completed the task with more error and increased medial hamstring and vastus medialis activation (p<0.05). Moderate negative correlations (p<0.05) were observed between quadriceps force control and medial (Spearman's rho=-0.448, p=0.022) and lateral (Spearman's rho=-0.401, p=0.034) hamstring activation in the ACLR group. Diminished quadriceps sub-maximal force control in ACLR subjects was reflective of medial quadriceps and hamstring dyskinesia (i.e., altered muscle activity patterns and coordination deficits). Within the ACLR group however, augmented hamstring co-activation was associated with better quadriceps force control. Future studies should explore the convergent validity of quadriceps force control in ACLR patients.
authors.affiliation: Department of Physiotherapy, Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, VIC, Australia.
authors.forename: Stacey
authors.initials: S
authors.lastname: Telianidis
authors.affiliation: Department of Physiotherapy, Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, VIC, Australia.
authors.forename: Luke
authors.initials: L
authors.lastname: Perraton
authors.affiliation: School of Exercise Science, Faculty of Health Sciences, Australian Catholic University, Melbourne VIC, Australia.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Clark
authors.affiliation: Department of Physiotherapy, Singapore General Hospital, Singapore.
authors.forename: Yong-Hao
authors.initials: YH
authors.lastname: Pua
authors.affiliation: Department of Physiotherapy, Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, VIC, Australia.
authors.forename: Karine
authors.initials: K
authors.lastname: Fortin
authors.affiliation: Department of Physiotherapy, Faculty of Medicine Dentistry and Health Sciences, The University of Melbourne, Melbourne 3010, VIC, Australia. Electronic address: albryant@unimelb.edu.au.
authors.forename: Adam L
authors.initials: AL
authors.lastname: Bryant
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D020820:Dyskinesias / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D052097:Quadriceps Muscle / Q000502:physiology*; D055815:Young Adult
keywords: ACL reconstruction; Force control; Hamstrings; Muscle activation; Quadriceps