title: Reliability of measuring hip and knee power and movement velocity in active youth.
abstract: OBJECTIVE
  The purpose of this study was to determine the reliability of measuring neuromuscular power and movement velocity of the hip and knee in young, active individuals using an isokinetic dynamometer.
  
  
  METHODS
  Peak power, average power, and peak velocity (PV) data were recorded for the hip in the standing position and the knee in the sitting position in 52 youth aged 10 to 14 years on 2 occasions approximately 1 week apart.
  
  
  RESULTS
  The PV measures demonstrated the best absolute reliability of all variables tested (coefficients of variation of the typical error [CV(TE)] = 5.0%-8.5%; standard errors of measurement = 18.1-21.1°/s). Hip flexion and knee extension peak power and average power exhibited acceptable reliability (CV(TE) = 8.7%-10.8%) compared with the other isokinetic tests (CV(TE) = 16.9%-32.8%).
  
  
  CONCLUSIONS
  Peak velocity appears to be a reliable means of indirectly measuring neuromuscular power in active youth, whereas direct measurement of power is only reliable for certain movements.
authors.affiliation: College of Rehabilitation Sciences, Faculty of Health Sciences (Dr Parsons), and Faculty of Kinesiology & Recreation Management, Health, Leisure and Human Performance Research Institute (Dr Porter), University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Joanne L
authors.initials: JL
authors.lastname: Parsons
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Porter
mesh_terms: D002648:Child; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D009119:Muscle Contraction; D053580:Muscle Strength / Q000502:physiology*; D018482:Muscle, Skeletal; D026741:Physical Therapy Modalities; D016059:Range of Motion, Articular; D015203:Reproducibility of Results