Reliability and Differences of Jump Kinetics Related to Different Load in College Male Athletes

The purpose of this study was to explore reliability and differences of jump kinetics related to different training load in college male athletes. The subjects were required to perform countermovement jump (CMJ) and loaded countermovement jump (LCMJ-0%, LCMJ-20% and LCMJ-80% of one-repetition maximum squat) three times for each load which were recorded by a force plate. One-way repeated measures ANOVA and the LSD post hoc method were employed to evaluate the results. The results reveled that jump kinetics-related parameters increased/decreased by the load. Compared with the loading jumps, the CMJ incorporate with an arm swing directly led to an increase in eccentric contraction duration during jumping. Most of the jump mechanical parameters under substantially different load conditions fall within the good to excellent reliability. It appears that the CMJ and CMJ with extra load were reliable in explore the kinetics related parameters. Keywords: countermovement jump, one-repetition maximum, arm swing, eccentric contraction

Relationship between anaerobic power and isokinetic trunk strength in college male soccer players

Background: Although anaerobic power affects soccer performance, the relationship between anaerobic power and core strength in soccer players has not been well studied. The aim of our study was to investigate the relationship between anaerobic power and core strength. Methods: The subjects were 31 college male soccer players. Their physical characteristics, anaerobic power (Wingate anaerobic test: WAnT), and core strength (isokinetic trunk strength test; ITST) were measured. To describe the effect of core strength on anaerobic power, the Pearson correlation coefficient and multiple regression analysis were conducted. Results: A significant relationship between the WAnT peak power (PP) and variables of ITST was observed (vs. trunk extension strength; TES: r = 0.629, vs. trunk flexion strength; TES: r = 0.507, vs. trunk extension power; TEP: r = 0.411, and vs. trunk flexion power; TFP: r = 0.555). We also found a relationship between the WAnT mean power (MP) and variables of ITST (vs. TES: r = 0.654, vs. TFS: r = 0.559, vs. TEP: r = 0.468, and vs. TFP: r = 0.720). The variables of ITST affecting WAnT PP were TES (P < 0.001) and TFP (P < 0.001). The explanatory power of these variables was 59.7% (R2 = 0.597). The variables of ITST affecting WAnT MP were TFS (P < 0.001) and TSE (P < 0.001). The explanatory power of these variables was 72.7% (R2 = 0.727). Conclusion: The results of our study showed that isokinetic trunk strength significantly associated with the WAnT peak and mean power.

System design and application for evaluation of digging agility in college male volleyball players

The primary objective of this study was to design a digging agility system that was used to analyze the effectiveness of 6 weeks of plyometric training on volleyball players. A total of 24 highly trained college male volleyball players were recruited for this study. The players were equally divided into a plyometric training group and a control group. The agility T-test, peak power output test, 10-meter sprint, and digging agility test were used to examine the effects of plyometric training on the digging agility of volleyball players. One-way analysis of covariance was conducted to examine the differences in the variables between groups. The results reveal that after 6 weeks of plyometric training, the plyometric training group had significant improvements on the agility T-test, digging agility test, and peak power output tests, with statistical power values all greater than 90%. The plyometric training group significantly improved by 2.68% on the agility T-test, 2.35% on the digging agility test, and 7.32% on the peak power output test. The results indicated that appropriate plyometric training can enhance the agility of lateral movements and peak output of vertical jumps, as well as enable players to rapidly complete movements during a moving defense.