Age-Related Development of Bilateral Coordination of the Upper Limbs in Children and Adolescents.

Bilateral coordination of the upper limbs (UL) is important for activities of daily living and physical activities. Motor coordination improves from childhood through adolescence. However, age-coordination trajectories for bilateral UL movements are not well-established, and it is unclear if bimanual coordination develops slower than unilateral coordination. In this study we examined age-related changes in UL coordination from childhood to late adolescence. Typically-developing children (N = 29, aged 7-17 years) performed unilateral and bilateral, antiphase cycling tasks with their ULs. Variations in cycling velocity and interlimb phase errors were computed as measures of coordination. Linear regression was used to examine age-coordination effects. Given the sensorimotor processing for bilateral movements and gradual development of the corpus callosum, we hypothesized different relationships between age and coordination for bilateral and unilateral movements. Results showed UL coordination was significantly related to age, where coordination was better in older compared to younger children (p < 0.001); however, there were similar significant effects for unilateral movements. Differences in unilateral and bilateral coordination were not significantly explained by biological sex, although power to detect sex differences was low. We conclude that bilateral and unilateral UL coordination are age-dependent; each improves at similar rates through childhood and adolescence.