title: Whole body and local muscle vibration reduce artificially induced quadriceps arthrogenic inhibition.
abstract: OBJECTIVE
  To evaluate the effects of whole body vibration (WBV) and local muscle vibration (LMV) on quadriceps function after experimental knee effusion (ie, simulated pathology).
  
  
  METHODS
  Randomized controlled trial.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Healthy volunteers (N=43) were randomized to WBV (n=14), LMV (n=16), or control (n=13) groups.
  
  
  METHODS
  Saline was injected into the knee to induce quadriceps arthrogenic muscle inhibition (AMI). All groups then performed isometric squats while being exposed to WBV, LMV, or no vibration (control).
  
  
  METHODS
  Quadriceps function was assessed at baseline, immediately after effusion, and immediately and 5 minutes after each intervention (WBV, LMV, control) via voluntary peak torque (VPT) and the central activation ratio (CAR) during maximal isometric knee extension on a multifunction dynamometer.
  
  
  RESULTS
  The CAR improved in the WBV (11.4%, P=.021) and LMV (7.3%, P<.001) groups immediately postintervention, but they did not improve in the control group. Similarly, VPT increased by 16.5% (P=.021) in the WBV group and 23% (P=.078) in the LMV group immediately postintervention, but it did not increase in the control group. The magnitudes of improvements in the CAR and VPT did not differ between the WBV and LMV groups.
  
  
  CONCLUSIONS
  Quadriceps AMI is a common complication following knee pathology that produces quadriceps dysfunction and increases the risk of posttraumatic osteoarthritis. Quadriceps strengthening after knee pathology is often ineffective because of AMI. WBV and LMV improve quadriceps function equivocally after simulated knee pathology, effectively minimizing quadriceps AMI. Therefore, these stimuli may be used to enhance quadriceps strengthening, therefore improving the efficacy of rehabilitation and reducing the risk of osteoarthritis.
authors.affiliation: Neuromuscular Research Laboratory; Department of Exercise and Sport Science; Program in Human Movement Science; Department of Orthopaedics. Electronic address: troyb@email.unc.edu.
authors.forename: J Troy
authors.initials: JT
authors.lastname: Blackburn
authors.affiliation: Neuromuscular Research Laboratory; Department of Exercise and Sport Science; Program in Human Movement Science.
authors.forename: Derek N
authors.initials: DN
authors.lastname: Pamukoff
authors.affiliation: Department of Family Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC.
authors.forename: Mark
authors.initials: M
authors.lastname: Sakr
authors.affiliation: Department of Family Medicine, Mountain Area Health Education Center, Asheville, NC.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Vaughan
authors.affiliation: Department of Orthopaedics.
authors.forename: David J
authors.initials: DJ
authors.lastname: Berkoff
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007270:Injections, Intra-Articular; D007537:Isometric Contraction / Q000502:physiology*; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D053581:Muscle Strength Dynamometer; D052097:Quadriceps Muscle / Q000503:physiopathology*; D012965:Sodium Chloride / Q000008:administration & dosage; D019415:Torque; D014732:Vibration / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D012965:Sodium Chloride
keywords: Anterior cruciate ligament; Knee; Osteoarthritis; Quadriceps muscle; Rehabilitation; Vibration