title: The effect of a single treatment of the Protonics system on biceps femoris and gluteus medius activation during gait and the lateral step up exercise.
abstract: BACKGROUND
  Patellofemoral pain, a frequent complaint among women, is attributed in part to excessive femoral internal rotation, leading to patellofemoral malalignment. The Protonics resistive dynamic knee orthosis was designed to facilitate hamstring activation, leading to a less anteriorly tilted pelvis and less femoral internal rotation. This decrease in femoral internal rotation is thought to improve patellofemoral joint alignment, thereby reducing knee pain. In this position, the gluteus medius (GM) would be more effective against the force of gravity. Therefore, this study's purpose was to determine the effects of a single application of the Protonics orthosis on knee pain and biceps femoris (BF) and GM activation.
  
  
  METHODS
  21 females (23.4+/-3.1 years, 1.66+/-0.05 m, 65.3+/-20.4 kg) with a history of chronic PFP participated in the study. Data were collected during level walking and a lateral-step up exercise in three conditions: pre-treatment (PRE), a placebo condition collected after the orthosis was set at zero resistance (PLAC), and post-treatment (POST). PLAC and POST were performed after the orthosis had been removed from the subject's leg. Percent of gait cycle activated, integrated EMG (IEMG), and level of pain (VAS scale) were measured in each condition. An ANOVA was used to determine significance between conditions (alpha=0.05).
  
  
  RESULTS
  Use of the Protonics orthosis did not result in any change in the level of knee pain, IEMG or duration of activation for the BF or GM.
  
  
  CONCLUSIONS
  Our results do not support an increase in hamstring activation or decrease in GM activation following a single treatment with the Protonics orthosis.
authors.affiliation: Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY 40506, USA. mccroryjl@msx.upmc.edu
authors.forename: Jean L
authors.initials: JL
authors.lastname: McCrory
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Quick
authors.forename: Robert
authors.initials: R
authors.lastname: Shapiro
authors.forename: Bryon T
authors.initials: BT
authors.lastname: Ballantyne
authors.forename: Irene
authors.initials: I
authors.lastname: McClay Davis
mesh_terms: D000328:Adult; D001915:Braces; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology; D007866:Leg / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*