Repeatability, consistency, and accuracy of hand-held dynamometry with and without fixation for measuring ankle plantarflexion strength in healthy adolescents and adults.

INTRODUCTION

Hand-held dynamometry (HHD) is commonly used to measure ankle plantarflexion strength but has variable reliability measuring higher forces. Fixed HHD is suggested to improve reliability. We, therefore, compared the reliability, consistency, and accuracy of measuring plantarflexion strength.

METHODS

Plantarflexion strength was measured in 25 healthy individuals with fixed HHD and HHD alone. Intraclass correlation coefficients (ICC ), SEM, minimal detectable change, and Spearman correlation coefficients were calculated to assess inter-trial repeatability, consistency, agreement, and accuracy.

RESULTS

Both methods were repeatable (ICC 0.96 to 0.98) and highly correlated (Spearman rho = 0.815; P < 0.01). Fixed HHD produced significantly higher force outputs. HHD alone provided more consistent force values.

CONCLUSIONS

Both methods of measuring ankle plantarflexion force were reliable. Force measured with fixed HHD will likely be more accurate for adults and individuals with greater strength, while HHD alone will be more consistent for individuals with lower strength. Muscle Nerve 56: 896-900, 2017.