title: Effect of exercise therapy on neuromuscular activity and knee strength in female adolescents with patellofemoral pain-An ancillary analysis of a cluster randomized trial.
abstract: Female adolescents with patellofemoral pain are characterized by altered neuromuscular knee control and reduced maximal quadriceps torque. The purpose of this study is to investigate whether exercise therapy and patient education are associated with larger improvements in neuromuscular knee control and maximal quadriceps torque compared with patient education alone.
  
  
  
  This is an ancillary analysis of a cluster randomized controlled trial investigating the effect of patient education and exercise therapy on self-reported recovery in 121 adolescents with patellofemoral pain. A random subsample of 57 female adolescents was included and tested at baseline and after 3months. Neuromuscular control of the knee was quantified as the complexity of surface electromyography of the vastus lateralis and vastus medialis during stair descent. Secondary outcomes were complexity of knee flexion/extension kinematics and maximal quadriceps torque.
  
  
  
  There was an 8-15% greater decrease in the complexity of surface electromyography suggesting an improvement in neuromuscular knee control among those randomized to exercise therapy (0.08<p<0.30). Adolescents randomized to exercise therapy had a 0.28-Nm/kg (95% CI: 0.05-0.52; p=0.02) larger increase in maximal quadriceps torque.
  
  
  
  Female adolescents randomized to patient education and exercise therapy had a significantly larger increase in maximal quadriceps torque and greater improvement in neuromuscular knee control during stair descent than those receiving patient education alone. This suggest that exercise therapy has an effect not only on self-reported outcome measures but also on objective measures of thigh muscle function in female adolescents with patellofemoral pain.
authors.affiliation: SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark; Orthopaedic Surgery Research Unit, Aalborg University Hospital, Denmark. Electronic address: misr@hst.aau.dk.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Rathleff
authors.affiliation: Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Afshin
authors.initials: A
authors.lastname: Samani
authors.affiliation: Institute of Sports Medicine Copenhagen, Copenhagen University Hospital, Bispebjerg, Denmark.
authors.forename: Jens L
authors.initials: JL
authors.lastname: Olesen
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Denmark.
authors.forename: Ewa M
authors.initials: EM
authors.lastname: Roos
authors.affiliation: Orthopaedic Surgery Research Unit, Aalborg University Hospital, Denmark; Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Sten
authors.initials: S
authors.lastname: Rasmussen
authors.affiliation: Physical Activity and Human Performance Group, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
authors.forename: Pascal
authors.initials: P
authors.lastname: Madeleine
mesh_terms: D000293:Adolescent; D001696:Biomechanical Phenomena; D004576:Electromyography; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D053580:Muscle Strength / Q000502:physiology; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology* / Q000628:therapy*; D052097:Quadriceps Muscle / Q000503:physiopathology*; D019415:Torque; D055815:Young Adult
keywords: Adolescents; Exercise therapy; Knee pain; Surface EMG