title: Reliability of the Superimposed-Burst Technique in Patients With Patellofemoral Pain: A Technical Report.
abstract: BACKGROUND
  The superimposed-burst (SIB) technique is commonly used to quantify central activation failure after knee-joint injury, but its reliability has not been established in pathologic cohorts.
  
  
  OBJECTIVE
  To assess within-session and between-sessions reliability of the SIB technique in patients with patellofemoral pain.
  
  
  METHODS
  Descriptive laboratory study.
  
  
  METHODS
  University laboratory.
  
  
  METHODS
  A total of 10 patients with self-reported patellofemoral pain (1 man, 9 women; age = 24.1 ± 3.8 years, height = 167.8 ± 15.2 cm, mass = 71.6 ± 17.5 kg) and 10 healthy control participants (3 men, 7 women; age = 27.4 ± 5.0 years, height = 173.5 ± 9.9 cm, mass = 78.2 ± 16.5 kg) volunteered.
  
  
  METHODS
  Participants were assessed at 6 intervals spanning 21 days. Intraclass correlation coefficients (ICCs [3,3]) were used to assess reliability.
  
  
  METHODS
  Quadriceps central activation ratio, knee-extension maximal voluntary isometric contraction force, and SIB force.
  
  
  RESULTS
  The quadriceps central activation ratio was highly reliable within session (ICC [3,3] = 0.97) and between sessions through day 21 (ICC [3,3] = 0.90-0.95). Acceptable reliability of knee extension (ICC [3,3] = 0.75-0.91) and SIB force (ICC [3,3] = 0.77-0.89) was observed through day 21.
  
  
  CONCLUSIONS
  The SIB technique was reliable for clinical research up to 21 days in patients with patellofemoral pain.
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville;
authors.forename: Grant E
authors.initials: GE
authors.lastname: Norte
authors.affiliation: Department of Health Sciences, James Madison University, Harrisonburg, VA.
authors.forename: Jamie L
authors.initials: JL
authors.lastname: Frye
authors.affiliation: Department of Kinesiology, University of Virginia, Charlottesville;
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Hart
mesh_terms: D016022:Case-Control Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007718:Knee Injuries / Q000175:diagnosis / Q000503:physiopathology; D007719:Knee Joint / Q000502:physiology; D008297:Male; D046788:Patellofemoral Pain Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D052097:Quadriceps Muscle / Q000502:physiology; D015203:Reproducibility of Results; D014495:Universities; D055815:Young Adult
keywords: central activation ratio; knee; quadriceps muscles