Validity and reproducibility of hand-held dynamometry in children aged 4-11 years.
OBJECTIVE
To evaluate validity and reproducibility of hand-held dynamometry in 11 different muscle groups in children.


METHODS
Maximum isometric muscle strength was measured with a calibrated hand-held dynamometer in 61 patients aged 4-11 years who had been referred to our specialist centre in the past 3 years because of suspected myopathy. All the patients had had muscle biopsy.


METHODS
Validity was assessed by the power to discriminate between patients with and without myopathy, using logistic regression analysis and receiver operating characteristic analysis and sensitivity and specificity at a specifically chosen cut-off point. Reproducibility was evaluated by test-retest reliability in a stratified random sample of 40 patients who returned for re-measurements, using the intraclass correlation coefficient and the standard error of measurement.


RESULTS
In the patients, areas under the receiver operating characteristic curve ranged from 0.66 to 0.88. At a specifically chosen cut-off point, sensitivity varied from 73% to 87%, while specificity varied from 54% to 80%. Intraclass correlation coefficients ranged from 0.73 to 0.91. The standard error of measurement ranged from 3.3 N to 12.2 N.


CONCLUSIONS
Performance of hand-held dynamometry varied widely in the 11 muscle groups. Highest performance was observed in the elbow flexors. Test-retest reliability of the mean value of 2 efforts was generally higher than the maximum value.
Department of Rehabilitation Medicine and Interdisciplinary Child Neurology Centre, University Medical Centre, Nijmegen St Radboud, Nijmegen, The Netherlands. w.vandenbeld@reval.umcn.nl
Willeke A
WA
van den Beld
Gitty A C
GA
van der Sanden
Rob C A
RC
Sengers
André L M
AL
Verbeek
Fons J M
FJ
Gabreëls
D002648:Child; D002675:Child, Preschool; D005260:Female; D018737:Hand Strength; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D009135:Muscular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity