Short-term Effect Of Explosive Isometrics Training On General Strength Performance And Biomechanical Index Of Judoka

Explosive Isometric Contraction is called Explosive Static Strength, Explosive Isometric training is an important method to develop power, it is not a new concept, which is studied by some scholars in the early 1970s, Explosive Isometric Contraction is a special pattern of isometric contraction, which emphasis isometric contract faster and harder to maximum force (MVF), known as fast isometric contraction. However, the studies related to Explosive Isometric Training is quite limited, and know less about short-term effect on strength performance, Purposes of the research are finding whether it has the short-term(2-4 weeks) effect through contrast with traditional power training, and providing theoretical basis and application reference for determining strength training before matches.Methods:17 subjects(high-level judo athletes), randomly divided into experimental group and control group, respectively undertook explosive isometric training and conventional explosive force training for 3 times a week, lasting for 4 weeks, subjects took general field strength test, plyometrics test and biomechanical test before and after training, also took general field strength test and plyometrics test on the second week. The test results were carried on statistics processing, compared the different effects.Results:4 weeks Explosive Isometric training has no significant effects on general strength performance and plyometrics as well as conventional power training.2 weeks explosive isometric group was significant better than conventional power group on biomechanical index such as the peak force(MVF), maximum RFD, peak time and time to maximum RFD, especially in the first half phase of F-t curve (50-100ms,100-150ms), but no significant difference in the last phase. There are no significant difference on normalized Force and normalized RFD. There are significant difference on Impulse especially in the last half phase(100-200ms).Conclusion:previous studies have shown that both training method can improve the maximum strength and explosive force, but this study shows that short-term(4 weeks) training has no significant effect on performance (general strength performance and Plyometrics), indicating that requires more than 4 weeks to improve dynamic strength performance; Two kinds of training has significant difference on influence of the mechanics index of isometric contraction forces, explosive isometric training has significant effect on the Peak Force (MVF), RFD and Peak Time, which are not changed by convention group;two trainings showed significant difference on biomechanical index in first half of isometric contraction curve(F-t), the second half of the difference disappeared, show that explosive isometric training has a positive influence to improve the starting strength (50-150ms). Efficiency in the short term training of Explosive isometric training has the practical application, and provides the theoretical support on enhancing athletic performance in the ultra short period training(2-4 weeks). Although there are differences influence on the mechanics index between two kinds of training, but the two groups have no significant difference on index standardization or normalization(%MVF), indicating that there should be correlation between isometric contraction mechanics index and peak force.