Symmetrical and Asymmetrical motor control in children : Bipedal and unipedal hopping

The purpose of this study was to compare the temporal and kinetic features of symmetrical and asymmetrical hopping in children of different ages. If the two hopping tasks become increasingly similar with age then one might hypothesise convergence of coordinative structures for repetitive hopping, encompassing unipedal and bipedal modes. Four groups of female children (N = 35), aged from 3.5 years to 9.5 years, were recruited. Temporal and kinetic variables were extracted from the ground reaction forces collected on a force plate sampling at 300 Hz. An Age x Task (repeated) ANOVA revealed a significant difference in unipedal and bipedal hopping in all timing and kinetic variables. Age groups differed in frequency, air duration, ground/air ratios and weight-normalised vertical impulses. Although task differences in kinetic parameters remained across age, some temporal variables became more alike. The temporal data appeared to provide tentative support for the hypothesis of convergence.