Comparison push-off and impact forces of aquatic jumps in different water depths

• Main Authors: Tsai, Teng-Chin, 蔡等進
• Other Authors: Chen, Wan-Chin
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/10465369940706022244

碩士 === 臺北市立大學 === 運動器材科技研究所 === 102 === This study aims at a comparison push-off force and landing impact forces of squat jump (SJ) and countermovement jump (CMJ) between on-land and in a pool with three different water levels. 14 male athletes were recruited from minor-league college volleyball teams. These participants first performed SJ and CMJ on land, and then performed the same aquatically in randomized manner in three different water levels: low level to the knee, middle level to the trochanter major and high level to the nasal. Each type of jumps was performed three times at an interval of one minute in each condition. Force data from jumps were measured by a force platform, and then those were calculated as force impulse and rate of force development during push off as well as the peak impact force and the impact force rate. All force parameters were normalized by the weight on land. A repeated analysis of variance with repeated measure was used for determining difference between the different water levels in pool and on land. The results showed that aquatic exercise produced a lower push-off force impulse than on-land exercise, but the exercises of SJ, no matter performed on land or aquatically in three different water levels, produced nearly the same push-off rate of force development. Moreover, CMJ on land and the aquatic exercises of CMJ in the middle and high water levels produced significantly higher rates of force development (7.04±2.94 BW•s-1, 6.23±1.81 BW•s-1 and 6.04±1.69 BW•s-1) than in the low water level (4.14±1.38 BW•s-1), and there were no significant difference between above three conditions. Jumps in pool with three different water levels produced significantly lower peak impact forces and impact force rate than the on-land exercise. Moreover, the aquatic exercises in the high and middle water levels produced lower landing impact forces than in the low water level with significance. Those results indicate that it would be most secure and effective to conduct jumping aquatically in the middle and high water level.