| Summary: | 碩士 === 國立臺灣體育學院 === 體育研究所 === 93 === ABSTRACT
The purpose of this study manipulated the variable of visual guidance, the effect of affordance, to investigate the age difference of kinematical characteristics for overarm throwing in children. Eight volunteer and right-handed boys for each age group (5-, 7-, 9-, and 11-year-old) served as participants in this study. Participants were asked to sit on the bench with legs straightly and to perform overarm throwing forcefully following the sequence of without and with visual guidance. Two high speed cameras (Redlake Motion Scope 1000, 250Hz) and the three-dimensional analysis system (SIMI version 7.0) were used to record and to digitize the throwing movements respectively. Mixed-design two-way ANOVA and Duncan’s test were adopted to analyze the statistical differences for developmental and the effect of visual guidance throwing with an alpha level of .05. The results showed the larger children threw that ball far (F(3, 28) = 22.54, p < .05, h2 = .71, power = 1.00). The main effect showed throwing with visual guidance (7.85 ± 2.76 m) was significant far than throwing without visual guidance (7.28 ± 2.81 m) (p < .05). The vertical velocity of release for throwing with visual guidance (3.44 ± 1.57 m/sec) was faster significantly than throwing without visual guidance (3.05 ± 1.53 m/sec), and the angle of release for throwing with visual guidance (17 ± 13 deg) was also higher significantly than throwing without visual guidance (11 ± 16 deg). The angular velocity of release on wrist for 11-year-old children (1038 ± 497 deg/sec) was higher significantly than 5-year-old (147 ± 637 deg/sec) under the condition of visual guidance. The maximal angular velocity (F(3, 56) = 3.59, p < .05) and angular velocity of release (F(3, 56) = 7.54, p < .05) on elbow were both showed age difference significantly. The angular velocity on elbow for late children was lager than middle children under the condition of visual guidance. For the group of 11-year-old, not only the angular velocity of release on wrist under the condition of visual guidance (1038 ± 497 deg/sec) was higher than the condition of without visual guidance (542 ± 752 deg/sec). But also the angular velocity of release on elbow under the condition of visual guidance (1186 ± 273 deg/sec) was higher than the condition of without visual guidance (864 ± 257 deg/sec). This study indicated that the effect of affordance, visual guidance, enhanced the performance of the throwing distance in the cause of vertical velocity of release to increase the angle of release. Under the condition of visual guidance, the pattern of throwing control on elbow was influenced before release. And there were age difference significantly on wrist and elbow at the moment of release. The angular velocity on wrist and elbow were increasing for 11-year-old children, but these were inconsistent for 5- to 9-year-old. From the aspect of the dynamical systems, the behavior of the development of throwing was constrained through the difference of task to process the effect of affordance positively.
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