优秀现代五项运动员“跑射联项”重心变化的非线性分析

Nonlinear Analysis on Variability of Pressure Center to Elite Modern Pentathlon Athletes in the Combined Event

目的:现代五项实施"跑射联项"新规则后彻底改变了原有射击比赛的制胜规律,使原有气手枪慢射改变为跑步后速射,跑步对于运动员重心变化的影响将决定着运动员的射击命中率。采用复杂度分析方法剖析"跑射联项"后运动员重心变化对于射击命中率的影响,进而提出最佳重心摆动模式。方法:模拟"跑射联项"过程,测试运动员在安静状态下及1 000m跑后瞄区变化轨迹,同时测试重心摆动。对运动前、后结果采用配对t检验(方差齐)和秩和检验(方差不齐)来衡量两者之间的显著性差异,同时采用非线性动力学的复杂度分析及Pearson相关分析来探讨重心变化的特征,以及其同射击命中率变化之间的关系。结果:在1 000m跑后运动员身体系统的复杂度同平静状态下相比有显著提高(P<0.05);运动前、后重心变化与其射击的命中率变的Pearson相关系数高达0.78,说明重心与运动员的命中率相关;重心轨迹变化呈现三类典型结果,即前后一字式、水平一字式和散点式,3种类型的优劣排序是前后一字式优于水平一字式优于散点式。结论:利用非线性动力学的相关知识发现了运动员运动后身体系统的复杂度同运动前相比显著性升高,而其变化的程度可能与运动员的竞技状态有关。同时,运动员在运动后命中率的显著下降同其运动后重心的变化有很高的相关性,并且重心的变化分为三种类型,是有一定规律的。

The new rule of modern pentathlon has changed the winning law in shooting game, that is, quick shooting after running replaced pistol in prior time. Thus, the impairment of running on the center of pressure for athletes is essential for the hitting rate. This paper uses com- plexity analysis to evaluate the influence of variability of center of pressure on the hitting rate for an athlete so that the best pattern of center of pressure could be displayed. Methods：We simulated the whole procedure of shooting to record the orbit of aiming point in quiet state and after 1000-meter race, accompanying with which the center of pressure was recorded, then utilized the T-test and rank sum test to evaluate whether there is significant difference between the two states. Meanwhile, nonlinear dynamical methods and Pearson correlation test were used to analyze the relationship between the change of COP and the hit rate. Results： It was found that there is significant increment in complexity of balance under physiological load accompanied by the significant decline of hitting rate compared to quiet state, of which the two have high correlation coherence （0.78）. Meanwhile, the results displayed that there are three typical types in the variability of the center of gravity, in which there is only one type we need in practice. Conclusions. In this study, we utilize nonlinear dynamical methods to find the complexity of athletes after running is significantly higher than in quiet, and the variance might be related to the state of athletes own. Meanwhile, the hitting rate decreases significantly after running, which is in high correlation with the change of COP, of which there exist three typical kinds of trajectory orbits. These findings have very important meaning for supporting new index and accordance to our training plan so that our athletes could improve their performances effectively.