Purpose: The aim of this study was to investigate the muscle strength and arch height of the foot in the standing position and the relations between these indices and physical performances involving the lower limbs in children.
Methods: A total of 301 elementary school children (third grade: n = 158, age = 8.6 ± 0.5 yr; fifth grade: n = 143, age = 10.6 ± 0.5 yr; means ± SD) participated. The maximal isometric toe flexor strength (TFS) in the standing position was measured using a toe flexor dynamometer. Foot arch height was assessed as the distance between the navicular tuberosity of the foot and the floor in the standing position, and foot arch height relative to the foot length was represented by the foot arch index (FAI). For physical performance involving the lower limbs, 50-m sprint, standing broad jump, repeated side step, and rebound jump were measured.
Results: There were no significant correlations between TFS and FAI and between relative TFS (relative TFS = TFS/body mass) and FAI. Relative TFS was significantly correlated with all physical performance tests. No significant correlations among FAI and physical performances were found, except for rebound jump ability in fifth graders. After multiple regression analyses adjusting for gender and body mass, TFS was the only significant correlating factor for all physical performances involving the lower limbs.
Conclusions: This study showed that TFS was associated with enhancement of some measures of lower limb physical performance in children. These results suggest that foot function should be evaluated with both the muscle strength and arch height of the foot in children.