A comparison of time characteristics in ball catching between children with and without Down's syndrome

摘要

Background : The one handed catching of a ball is a complex coordination ability. It requires the spatial and time adjustment of the hand according to the speed of the approaching ball. Objective : Two main objectives were exposed in the course of the present research; namely whether and why children with Down's syndrome (DS) have problems with one handed ball catching compared to the children with no impairment in motor task such as the one handed catching of a ball. Methods : Eleven children with DS, aged 8, and 16 with no impairment, also aged 8, were required to catch 45 balls (small, medium, and large). No spatial uncertainty regarding the trajectory of the ball was present and therefore only time judgements were required to catch the ball. Results : The results of the present research showed that children with DS missed more balls than the children from the control group; the children with DS missed 30% of the balls vs. the children from the control group, who missed 7% of the balls. In addition, children with DS missed more small balls. The kinematic analysis of the time characteristics of one handed catching revealed that the difference in timing occurs at the time of grasping the ball. When examining the time of the catch in relationship to the time window, it can be seen that most children with DS tended to finish their catch too late. Conclusions : Since differences were not found for the time of initiation and the time of maximal aperture, the present experiment suggests that it is not so much the anticipatory control but a slowness of movement that causes the higher percentage of catching failures in the children with DS.