title: Immediate Effect of Patterned Electrical Neuromuscular Stimulation on Pain and Muscle Activation in Individuals With Patellofemoral Pain.
abstract: BACKGROUND
  For individuals with patellofemoral pain (PFP), altered muscle activity and pain are common during functional tasks. Clinicians often seek interventions to improve muscle activity and reduce impairments. One intervention that has not been examined in great detail is electrical stimulation.
  
  
  OBJECTIVE
  To determine whether a single patterned electrical neuromuscular stimulation (PENS) treatment would alter muscle activity and pain in individuals with PFP during 2 functional tasks, a single-legged squat and a lateral step down.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  Sports medicine research laboratory. PATIENTS OF OTHER PARTICIPANTS: A total of 22 individuals with PFP (15 women, 7 men; age = 26.0 ± 7.9 years, height = 173.8 ± 8.1 cm, mass = 75.1 ± 17.9 kg).
  
  
  METHODS
  Participants were randomized into 2 intervention groups: a 15-minute PENS treatment that produced a strong motor response or a 15-minute 1-mA subsensory (sham) treatment.
  
  
  METHODS
  Before and immediately after the intervention, we assessed normalized electromyography amplitude, percentage of activation time across functional tasks, and onset of activation for the vastus medialis oblique, vastus lateralis, gluteus medius, adductor longus, biceps femoris, and medial gastrocnemius muscles during a single-legged squat and a lateral step down. Scores on the visual analog scale for pain were recorded before and after the intervention.
  
  
  RESULTS
  After a single treatment of PENS, the percentage of gluteus medius activation increased (0.024) during the lateral step down. Visual analog scores decreased during both the single-legged squat (PENS: preintervention = 2.7 ± 1.9, postintervention = 0.9 ± 0.7; sham: preintervention = 3.2 ± 1.6, postintervention = 2.8 ± 1.9; group × time interaction: P = .041) and lateral step down (PENS: preintervention = 3.4 ± 2.4, postintervention = 1.1 ± 0.8; sham: preintervention = 3.9 ± 1.7, postintervention = 3.3 ± 2.0; group × time interaction: P = .023). No changes in electromyography or pain measures were noted in the sham group.
  
  
  CONCLUSIONS
  The PFP participants who received PENS had immediate improvement in gluteus medius activation and a reduction in pain during functional tasks.
authors.affiliation: Department of Kinesiology, Exercise & Sport Injury Laboratory, University of Virginia, Charlottesville.
authors.forename: Neal R
authors.initials: NR
authors.lastname: Glaviano
authors.affiliation: Department of Kinesiology, Exercise & Sport Injury Laboratory, University of Virginia, Charlottesville.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Saliba
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy; D004576:Electromyography; D005260:Female; D006615:Hip; D006801:Humans; D007866:Leg; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010147:Pain Measurement; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology* / Q000628:therapy*; D013848:Thigh; D055815:Young Adult
keywords: anterior knee pain; myoelectric stimulation; therapeutic modalities