The link from the joint and relative phase view in adolescent girls overarm throwing exercises degrees of freedom phase transitions.

• Main Authors: Liu Hong-Jui, 劉洪瑞
• Other Authors: Chiu Wen-Hsinn
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/66569864253523960976

碩士 === 國立新竹教育大學 === 人資處體育碩士專班 === 100 === The purpose of the study was to investigate the differences among the participants in the tennis ball overarm throwing performances among different settings (before practice, after practice, and during the retention period). Ten adolescents girls were selected to serve as the subjects for this study. Each subject has to practice 720 times of tennis ball overarm throwing during eight weeks. Two Hi-Speed cameras (CASIO EX-F1, 300Hz) were used to record the throw performances. The Kwon 3D Software was applied to analyze the collected data. The ANOVA Repeated Measure was used to analyze the different initial ball speeds before practice, after practice, and during the retention period. Pearson product-moment correlation was applied to analyze the relationship between the initial ball speeds during the maxima angle and the maxima angular velocity. In additions, the angle-angle plot was also applied to explain the performance differences among different settings s. The results show that: (1) there were significant differences among different settings (before practice, after practice, and during the retention period)（p＜.05）; (2) there was significant relationship between the initial ball speeds of the maxima shoulder joint angle and the maxima wrist joint angle after practice（p＜.05）; (3) there was no significant relationship among different initial ball speeds for different settings (before practice, after practice, and during the retention period); however, the angle speeds of the upper body joints after practice are faster than those speeds before practice; (4) the angle-angle plot shows that the joint angle motions became more complicated after practice ;while the joint angle motions before practice are similar to those during the retention period. Besides, the wrist and elbow joint angles became wider after practice, but both angles came back to the previous angles (before practice) during the retention period.