title: Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable.
abstract: OBJECTIVE
  In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamometer may resolve this. The aim of the present study was therefore to examine the inter-tester reliability concerning strength assessments of isometric hip abduction, adduction, flexion, extension and knee-flexion strength, using HHD with external belt-fixation.
  
  
  METHODS
  Twenty-one healthy athletes (6 women), 30 (8.6) (mean (SD)) years of age, were included. Two physiotherapy students (1 female and 1 male) performed all the measurements after careful instruction and procedure training. Isometric hip abduction, adduction, flexion, extension, and knee-flexion strength were tested. The tester-order and hip-action order were randomised.
  
  
  RESULTS
  No systematic between-tester differences (bias) were observed for any of the hip or knee actions. The intra-class correlation coefficients (ICC 2.1) ranged from 0.76 to 0.95. Furthermore, standard errors of measurement in per cent (SEM %) ranged from 5 to 11 %, and minimal detectable change in per cent (MDC %) from 14 to 29 % for the different hip and knee actions.
  
  
  CONCLUSIONS
  The present study shows that isometric hip- and knee-strength measurements have acceptable inter-tester reliability at the group level, when testing strong individuals, using HHD with belt-fixation. This procedure is therefore perfectly suited for the evaluation and monitoring of strong athletes with hip, groin and hamstring injuries, some of the most common and troublesome injuries in sports.
  
  
  METHODS
  Diagnostic, Level III.
authors: Arthroscopic Centre Amager, Copenhagen University Hospital, Hvidovre, Italiensvej 1, 2300, Copenhagen S, Denmark. kristianthorborg@hotmail.com
authors: Kristian
authors: K
authors: Thorborg
authors: Thomas
authors: T
authors: Bandholm
authors: Per
authors: P
authors: Hölmich
mesh_terms: D000328:Adult; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction; D007717:Knee / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D053581:Muscle Strength Dynamometer; D015588:Observer Variation; D015203:Reproducibility of Results; D055815:Young Adult