Effect of motor development levels on kinematic synergies during two-hand catching in children

The ability to coordinate different body parts under different constraints that are imposed by organism, environment and tasks during motor development might be different in children. The aim of this study was to examine whether children with different motor development levels are different with regard to multi-joint coordination during two-hand catching. Eighty-four children (age: 6.05 ± 0.67years) who were assessed on object control skills were recruited voluntarily. The biomechanical model was defined from 20 movements of 7 segments (shoulders, elbows, wrists and torso), and the principal component analysis was used to quantify the multi-joint coordination and kinematic synergies during the catching. The results showed that the redundancy of joints in two-hand catching is controlled by three kinematic synergies that defined the majority of the variance. The participants that were grouped based on their development levels did not show differences in the numbers and strength of synergies; however, they were different in the utilisation of the kinematic synergies for successful catching. In conclusion, the numbers and the strength of kinematic synergies during two-hand catching are not affected by the developmental levels, and are related to the nature of the task