Long-term stability of hand-held dynamometric measurements in children who have myelomeningocele.

The long-term stability of hand-held dynamometric measurements was assessed in 30 muscle groups of 12 children with myelomeningocele, before and after a 23-day interval. Measurements from a majority of the muscle groups had excellent stability, based on statistical indicators of association (Pearson Product-Moment Correlation Coefficients, r =.76-.98) and agreement (intraclass correlation coefficients, ICC = .75-.99). Muscle groups with lower long-term stability were the right and left wrist extensors and flexors, the left hip adductors and extensors, the left knee flexors, and the right and left knee extensors. Upper-extremity muscle groups had higher long-term stability than did lower-extremity muscle groups. The results indicate that the dynamometric measurements were highly reliable when the test-retest interval was 23 days. Other researchers have previously shown high reliability for these measurements over shorter periods of time. Improved reliability might be obtained by supporting the lower extremity during hip extension tests; padding the dynamometer end pieces, especially when testing over bony prominences; and using a smaller, digital dynamometer. The hand-held dynamometer appears to warrant use and further investigation with pediatric populations.