[[alternative]]A Quantitative Research on Volleyball Players’ Lower Limbs Strength Performance and Different Ways of Isotonic Strength Training

[[abstract]]The study aims to use quantitative measurement to evaluate the effect of different ways of isotonic strength training on the volleyball players’ lower limbs strength, maximal contraction velocity, jump height and energetic power’s performances. In addition, the correlation among the four kinds of performances will also be discussed. The data was collected from 30 male subjects. They were college volleyball players, who belonged to two school teams in the 2000 academic year and the 2004 academic year respectively. After different Ways of isotonic training, these subjects were examined and measured with four kinds of performances: lower limbs strength, maximal contraction velocity, jump height and energetic power. Two statistical tests, t-test and Pearson Correlation were used to analyze the data. The results of the study show that there is a positive correlation between two kinds of performances: maximal contraction velocity and jump height; the r value is 0.884. However, there is no positive correlation among the other kinds of performances. Besides, there are two significant differences (the p value < 0.05) between the two teams of subjects in the performances of maximal contraction velocity and jump height. The mean differences are 0.25m/sec and 0.18m/sec respectively. While, there are no significant differences between the two teams of subjects in the performances of lower limbs strength and energetic power. Another important finding in the study is that plyometric training has positive effect on enhancing contraction velocity and continuous smashing training can improve the height of jumping. Furthermore, the study also suggests making good use of action plyometric training to train the volleyball players.