论短跑摆腿技术的特点

近年来，随着田径运动技术水平的提高和发展，短跑的技术也有所变化，更加强调摆腿技术的重要性。摆腿的速度、力量、方向、幅度都直接影响着后蹬的效果。只有加强摆腿技术，才能更好地促进后蹬，只有提高蹬、摆的配合效果，才能更快，更好地提高运动成绩。     

Spawning behaviour of Engystomops pustulatus (Anura: Leptodactylidae)

Foam nests have evolved independently in several amphibian groups as an adaptive response to prevent predation and desiccation in dry environments. Nests are normally laid on ponds, or in underground galleries, humid forest leaf litter or terrestrial bromeliads. They are built when males or females beat a foam precursor associated with the egg masses extruded by the female. The spawning process requires the synchronic actions of the mating pair to obtain a hemispheric nest that protects the offspring. Herein, we describe the spawning behaviour of Engystomops pustulatus based on videos from 13 nesting couples from the lowlands of western Ecuador. Three variables were measured as indicators of male effort: duration of mixing events, duration of resting periods, and number of kicks per mixing event. We consider that not only male physical effort but also female behaviour influences nest structure. We suggest that nest building requires prolonged and intense physical activity by the male as well as the female’s steady position during spawning and female’s oviposition site selection. Nest building has two phases. In the first phase, the duration of resting periods, the duration of mixing events, and the number of kicks increase and are highly variable. During the second phase the three variables stabilise until the end. The volume of the nest increased mainly during the second phase. In four nesting events we observed kicking movements by the female. To our knowledge, this is the first time that female kicking has been observed in leptodactylid frogs. The function of this behaviour is unknown but our observations suggest that it may be triggered by insufficient male effort. Traditionally, female mate choice in Engystomops has been explained under models of indirect benefits exclusively. We argue that the prolonged male activity during nesting could influence female fitness directly. This will allow the operation of sexual selection via direct benefits.     

试论武术实用技法

本文分三个部分从理论上阐述了武术的实用技法,即拳法、腿法、摔法及其在散手比赛中的实际运用。要求运动员不仅要具备全面的身体素质和技术水平,而且要能合理地运用战术,发挥个人长处,并力求使用简单而实用的方法去战胜对手取得胜利。     

浅谈排球比赛中的脚击球

新规则允许排球可以接触身体的任何部分,使得脚可以击球.本文就脚击球做为防守中一项新技术,谈其在比赛中的运用情况.     

关于速滑蹬冰动作的实效性分析

运用运动生物力学方法,对膝关节在蹬冰过程中的动态变化进行了分析,并采用人体肢体检测与恢复系统,对膝、髋伸肌群的工作特点进行了探讨.结果表明:(1)膝关节点在蹬伸过程中的位置变化是向前并且向下,而髋关节点却是向前且偏上;(2)左、右伸膝肌群峰值力矩在高速区有显著性差异,240(°) s以上是速滑的常用速度区;(3)训练中肌群力量的发展往往有收缩速度区的差别.     

有氧搏击操锻炼对男大学生体质的影响

选取60名不同专业男大学生为研究对象,测定其经过13周有氧搏击操锻炼前后体质变化,研究有氧搏击操对男大学生体质的影响.实验结果表明：有规律的有氧搏击操锻炼能有效地改善男大学生的身体形态,提高身体机能水平,促进身体素质的发展,从而对体质产生积极有效的影响.