title: Immediate Effects of Therapeutic Ultrasound on Quadriceps Spinal Reflex Excitability in Patients With Knee Injury.
abstract: OBJECTIVE
  To investigate the effects of nonthermal therapeutic ultrasound on quadriceps spinal reflex excitability in patients with knee joint injury.
  
  
  METHODS
  Double-blind, randomized controlled laboratory study with a pretest posttest design.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  Recreationally active volunteers with a self-reported history of diagnosed intra-articular knee joint injury and documented quadriceps dysfunction (N=30).
  
  
  METHODS
  A nonthermal ultrasound, or sham, treatment was applied to the anteromedial knee.
  
  
  METHODS
  Hoffmann reflex measurements were recorded at baseline, immediately postintervention, and 20 minutes post-intervention. The peak Hoffmann reflex amplitude was normalized by the peak motor response (H/M ratio) measured from the vastus medialis using surface electromyography as an estimate of quadriceps motorneuron pool excitability. A repeated-measures analysis of variance was used for comparisons.
  
  
  RESULTS
  A significant group-by-time interaction was observed for mean (P=.016) and change (P=.044) in H/M ratio. The ultrasound group demonstrated significantly higher mean (P=.015) and change (P=.028) in H/M ratio 20 minutes postintervention than did the sham ultrasound group.
  
  
  CONCLUSIONS
  Quadriceps motoneuron pool excitability was facilitated 20 minutes after a nonthermal therapeutic ultrasound treatment, and not a sham treatment. These data provide supporting evidence of the contribution of peripheral receptors in modulation of the arthrogenic response in patients with persistent quadriceps dysfunction. Future research in this area should attempt to identify optimal treatment parameters and translate them to clinical outcomes.
authors.affiliation: Department of Kinesiology, Sports Medicine Program Area, University of Virginia, Charlottesville, VA. Electronic address: gen5e@virginia.edu.
authors.forename: Grant E
authors.initials: GE
authors.lastname: Norte
authors.affiliation: Department of Kinesiology, Sports Medicine Program Area, University of Virginia, Charlottesville, VA.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
authors.affiliation: Department of Kinesiology, Sports Medicine Program Area, University of Virginia, Charlottesville, VA.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D004576:Electromyography; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000534:rehabilitation*; D008297:Male; D009046:Motor Neurons / Q000502:physiology; D052097:Quadriceps Muscle / Q000000981:diagnostic imaging*; D012018:Reflex / Q000502:physiology*; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography
keywords: Central nervous system; Motor neurons; Neural pathways; Neuromuscular manifestations; Reflex; Rehabilitation