抄録
The purpose of this study was to examine the differences in throwing movements and exercise play habits between children 4-5 years old with initially low throwing ability who improved and children who did not improve.
We administered an initial softball throwing test for 4-year-old boys (n=105), and then selected 14 boys with low throwing ability ( ≤ 3m). Five of the boys with initially low throwing ability improved and were classified as the “improvement group.” Nine boys with initially low throwing ability did not improve and were classified as the “stagnation group.” We filmed their throwing motions and analyzed the movements three-dimensionally by using Frame-DIAS IV. To examine their exercise play habits, we questioned their class teacher on the frequency and content of exercise play.
The analyses revealed that in 5-year-olds, the improvement group showed significantly higher ball velocity, greater rotational range and higher rotating angular velocity of the shoulder, and higher extending angular velocity of the elbow than did the stagnation group. Additionally, all children in the improvement group stepped forward with the foot opposite their throwing arm when throwing. There were no significant differences in exercise play habits of 4-year-olds between the improvement and stagnation groups. However, in 5-year-olds, the improvement group played with a ball significantly more than the stagnation group. Furthermore, the 4-year-olds in the stagnation group engage in play that did not require much movement significantly more than the improvement group.
We suggest that for 4-year-olds, playing actively outside was essential to improve throwing ability, and that for 5-year-olds, playing with a ball and learning through
experience how to rotate the shoulder while throwing were necessary to improve throwing ability.
