Abstract

Motion analysis of the arm movements of 12 boys, aged 11 years, was carried out from video tape records of their efforts to catch (one-handed) a tennis ball rebounded toward them on a consistent trajectory. It was predicted that upper arm velocity immediately preceding finger grasp would be significantly higher when the ball was dropped. The results supported the proposition showing that upper arm motion began later and was more than twice as fast at a point when the fingers were ready to secure the ball although there were no differences in peak velocity. It was concluded that dyscontrol results if proximal activity (upper arm motion) intrudes upon distal activity (timing of finger grasp) as the ball is received and will problably result in it being dropped. Verf.-Referat