title: Is hand-held dynamometry useful for the measurement of quadriceps strength in older people? A comparison with the gold standard Bodex dynamometry.
abstract: BACKGROUND
  The lower limb muscle strength is an important determinant of physical function in older people. However, measurement in clinical and epidemiological settings has been limited because of the requirement for large-scale equipment. A protocol using a novel, versatile hand-held dynamometer (HHD) has been developed to measure the quadriceps strength in a supine position.
  
  
  OBJECTIVE
  The objective of this study was to assess the validity of this new methodology for measuring the lower limb muscle strength compared to the gold standard Biodex dynamometer.
  
  
  METHODS
  The supine quadriceps strength was measured twice with each of the Biodex and the HHD in 20 men and women, aged 61-81 years, on their non-dominant leg. The agreement between the peak torques obtained by Biodex and HHD was analyzed.
  
  
  RESULTS
  The mean peak Biodex and HHD results were 83.4 +/- (SD) 28.0 Nm and 68.9 +/- 19.6 Nm, respectively. The HHD undermeasured the quadriceps strength by an average of 14.5 Nm (95% CI 8.5, 20.6) compared to the Biodex, and this effect was most marked in the strongest participants. Nevertheless, there was a good correlation between the measures (r = 0.91, p < 0.0001). Classification of individuals into tertiles of muscle strength showed good agreement between the two methods (Kappa = 0.69, p < 0.0001).
  
  
  CONCLUSIONS
  Our findings suggest that the HHD using a supine positioning offers a feasible, inexpensive, and portable test of quadriceps muscle strength for use in healthy older people. It underestimates the absolute quadriceps strength compared to the Biodex particularly in stronger people, but is a useful tool for ranking muscle strength of older people in epidemiological studies. It may also be of value for quick and objective assessment of physical function in the clinical setting.
authors.affiliation: MRC Epidemiology Resource Centre, University of Southampton, Southampton, UK. hjm@mrc.soton.ac.uk
authors.forename: H J
authors.initials: HJ
authors.lastname: Martin
authors.forename: V
authors.initials: V
authors.lastname: Yule
authors.forename: H E
authors.initials: HE
authors.lastname: Syddall
authors.forename: E M
authors.initials: EM
authors.lastname: Dennison
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.forename: A
authors.initials: A
authors.lastname: Aihie Sayer
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018763:Muscle Fatigue / Q000502:physiology; D052097:Quadriceps Muscle / Q000502:physiology*; D015203:Reproducibility of Results; D016683:Supine Position / Q000502:physiology