Effects of Drop Jump Starting Height on Eccentric Utilization Ratio and Reactive Strength Index

• Main Authors: Chang, Chin-Jung, 張晉榮
• Other Authors: Chen, Chung-Yu
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/12478100140618329822

碩士 === 國立臺灣體育運動大學 === 體育研究所 === 105 === The purposes of this study were to compare the effect of the heights of drop jump on the index of stretch shortening cycle (SSC), and to correlate estimates of the indexes of SSC derived from the joints of lower extremity and jump height. Fourteen male physical education university students were recruited as the participants voluntarily for this study. The mean age, height, and body mass of the participants were 21.6 ± 2.9 years old, 172.1 ± 2.9 cm, and 68.6 ± 4.4 kg, respectively. Each participant was asked to perform squat jump (SJ), counter movement jump (CMJ), 20 cm drop jump, 40 cm drop jump, and 60 cm drop jump randomly. Eight Vicon infrared digital cameras (MX F40, 300 Hz) and two Kistler force platforms (9260AA6, 1500 Hz) were synchronized to acquire the kinematical and kinetical data respectively. The pre-stretch augmentation percentage (PSAP), the eccentric utilization ratio (EUR), the reactive strength (RS), and the reactive strength index modified (RSImod) were used to assess the explosiveness developed during the variety of jumps. Correlations were determined using Pearson’s r and differences among jumps were determined using repeated measures one way ANOVA and HSD post-hoc for biomechanical parameters with the alpha level .05. The results showed the CMJ was the highest jump in this study, but there were no significant different among three heights of DJ. The PSAP, EUR, and RS of CMJ that estimated by the jump height were higher than three heights of DJ, but the RSImod of three heights of DJ were higher than CMJ, significantly. The correlations analysis showed the RSImod derived from peak power of knee extensor and plantar flexor during concentric phase were strongly related positively to the RSImod derived from jump height. It indicated that RSImod derived from the jump height could explain the concentric performance of CMJ or DJ on knee and ankle.