Variability in motor coordination: an approach based on the twin design

Abstract

The purpose of this study was to estimate the contribution of environmental and genetic factors on the variability of interindividual performance in motor coordination. Sample comprised 64 twin pairs, aged 5 to 14 years old, from Portugal. Motor coordination was evaluated by KTK battery: backward balance (ER); hopping on one leg (SM); shifting platforms (TL); jumping sideways (SL). Intraclass correlation coefficient (t) was calculated. Contributions of genetic (a²), shared (c²) and unique environmental (e²) factors were estimated. Our results showed t values higher in monozygotic twins, suggesting the presence of genetic factors. Nevertheless, a² estimates were low, ranging from 15% (TL) to 41% (SM), while to common environment (c²) ranged from 46% (SL) to 58% (TL), and unique effects ranged from 11% (SM) to 28% (TL). These results suggest that environmental factors are responsible for the greatest part of influence on variability of interindividual performance in motor coordination tests.