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Validity and reproducibility of hand-held dynamometry in children aged 4-11 years
Willeke A van den Beld1, Gitty A C van der Sanden, Rob C A Sengers
1Department of Rehabilitation Medicine and Interdisciplinary Child Neurology Centre, University Medical Centre, Nijmegen St Radboud, Nijmegen, The Netherlands. w.vandenbeld@reval.umcn.nl
Insights
Hand-held dynamometry shows variable validity and reproducibility in pediatric muscle groups. Elbow flexors demonstrated the highest performance, with test-retest reliability improving when using mean values over maximum efforts.
Area of Science:
- Pediatric physical therapy
- Neuromuscular diagnostics
- Musculoskeletal assessment
Background:
- Hand-held dynamometry is increasingly used for muscle strength assessment in children.
- Its validity and reproducibility across various muscle groups in pediatric populations require thorough evaluation.
- Accurate strength measurements are crucial for diagnosing and monitoring neuromuscular disorders.
Purpose of the Study:
- To assess the validity and reproducibility of hand-held dynamometry across 11 distinct muscle groups in children.
- To determine the diagnostic accuracy of this method in differentiating between children with and without myopathy.
- To evaluate the reliability of repeated measurements for muscle strength evaluation.
Main Methods:
- Isometric muscle strength was measured using a calibrated hand-held dynamometer in 61 children (aged 4-11 years) with suspected myopathy.
- Validity was determined using logistic regression and receiver operating characteristic (ROC) analysis to discriminate between myopathic and non-myopathic groups.
- Reproducibility was assessed via test-retest reliability in 40 patients using intraclass correlation coefficients (ICC) and standard error of measurement (SEM).
Main Results:
- Areas under the ROC curve ranged from 0.66 to 0.88, indicating variable diagnostic performance across muscle groups.
- Sensitivity ranged from 73% to 87%, and specificity from 54% to 80% at chosen cut-off points.
- Intraclass correlation coefficients (ICC) for reproducibility were generally high (0.73-0.91), with SEMs ranging from 3.3 N to 12.2 N.
Conclusions:
- Hand-held dynamometry performance varied significantly across the 11 assessed pediatric muscle groups.
- Elbow flexors exhibited the highest validity and reproducibility.
- Test-retest reliability was generally better when using the mean of two efforts compared to the maximum single effort.
Objective:
To evaluate validity and reproducibility of hand-held dynamometry in 11 different muscle groups in children.
Design And Patients:
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.
Conclusion:
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.
