Foot motion in children and adults

When studying the function of the human foot, foot pressure measurements offer some insight into the biomechanics of the growing foot [1] and models have been proposed to measure the foot kinematics especially of children [2]. Aside from ankle kinematics however [3], little is known about differences in foot motion between children and adults. This ongoing study therefore examines the foot kinematics of normal subjects in a large age range.

Normal feet of 30 children aged 4–11 years (mean 7.8 yrs) and of 24 adults aged 19–51 years (mean 32.4 yrs) have been examined by instrumented gait analysis using the Heidelberg foot measurement method (HFMM) [4] with the marker set illustrated in Figure 1. In this method, the motion of the hind foot is described relative to the tibia by tibio-talar (ankle) flexion and subtalar rotation. For mid- and forefoot motion, functional parameters are evaluated which are relevant for a clinical evaluation forming together a standardized set of 12 angles. The ROM in each angle has been determined across the gait cycle as a "dynamic" evaluation. Further, these parameters have been evaluated in mid swing to find "static" differences with respect to age in the geometry of the unloaded foot. A student T-Test was used to evaluate differences between the feet of children and adults.

Data are summarized in Table 1. We find a smaller ROM across the gait cycle in (conventional) ankle flexion for children in agreement with [3] and specifically a smaller ROM in tibio-talar flexion. Further, children show smaller ROMs in forefoot supination and adduction. Most prominent "static" findings in mid swing were a higher cavus (smaller medial arch angle) and less divergent metatarsals (MT 1–5 angle) with also a smaller ROM in children compared to adults.

In normal walking, foot motion in children differs significantly to foot motion in adults with respect to forefoot and hind foot motion.