title: Electric muscle stimulation of the quadriceps in the treatment of patellofemoral pain.
abstract: OBJECTIVE
  To compare a commercially available electric muscle stimulation regimen with a novel form of stimulation for the rehabilitation of the quadriceps muscle, in patients with patellofemoral pain syndrome.
  
  
  METHODS
  Double-blinded randomized trial with a parallel control group and stratified randomization.
  
  
  METHODS
  Home-based rehabilitation program assessed in research center.
  
  
  METHODS
  Eighty patients (47 women, 33 men) with patellofemoral pain syndrome.
  
  
  METHODS
  One group (EMPI) received 1 uniform constant frequency component of 35Hz. The other (EXPER) group received an experimental form of stimulation that contained 5 simultaneously delivered frequency components of 125, 83, 50, 2.5, and 2Hz. Stimulation was applied to the quadriceps muscles of the affected leg for 1 hour daily for 6 weeks, a total of 42 treatments.
  
  
  METHODS
  Lower-limb isometric and isokinetic torque, quadriceps fatigue, knee flexion, patellar pain, a step test, quadriceps cross-sectional area, and Kujala patellofemoral score for pain before and after treatment.
  
  
  RESULTS
  Seventy-four patients (43 women, 31 men) completed the trial. Patients in both groups showed significant improvements in all outcomes (P<.05). No significant differences existed between the 2 stimulators in any outcome (P>.05) except for quadriceps cross-sectional area (P=.023).
  
  
  CONCLUSIONS
  One form of stimulation was just as efficacious as the other in improving subjective and objective measures.
authors.affiliation: Centre for Rehabilitation Science, Manchester Royal Infirmary, Oxford Road, Manchester M13 9WL, UK. michael.callaghan@man.ac.uk
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Callaghan
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Oldham
mesh_terms: D000328:Adult; D018771:Arthralgia / Q000534:rehabilitation*; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging / Q000503:physiopathology*; D017063:Outcome Assessment, Health Care; D019415:Torque; D014463:Ultrasonography