Relationship between foot strength and motor function in preschool-age children.

Foot weakness occurs in many paediatric neuromuscular disorders, which overtime can cause considerable functional motor difficulties. Measuring foot strength with hand-held dynamometry is reliable in preschool-age children, but its validity in this age group is unknown. If foot strength measures are collected as endpoints in clinical trials, they should represent functionally meaningful outcomes. We evaluated the foot strength-motor function relationship in 60 healthy children aged 2-4 years. Foot strength measures included inversion, eversion, dorsiflexion and plantarflexion using hand-held dynamometry. Motor function parameters included time to run 10-m, standing long jump distance and vertical jump height. Measures of foot strength showed significant correlations with all measures of motor function (r=0.40-0.57, p<0.001). Hand-held dynamometry may be used as a valid and functionally meaningful measure of foot strength in very young children.