Enoka R M
Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721.
Med Sci Sports Exerc. 1988 Apr;20(2):178-87. doi: 10.1249/00005768-198820020-00013.
An exemplary short duration, high-power, weightlifting event was examined to determine whether the ability to lift heavier loads and whether variations in the level of skill were accompanied by quantitative changes in selected aspects of lower extremity joint power-time histories. Six experienced weightlifters, three skilled and three less skilled, performed the double-knee-bend execution of the pull in Olympic weightlifting, a movement which lasted almost 1 s. Analysis-of-variance statistics were performed on selected peak and average values of power generated by the three skilled subjects as they lifted three loads (69, 77, and 86% of their competition maximum). The results indicated that the skilled subjects lifted heavier loads by increasing the average power, but not the peak power, about the knee and ankle joints. In addition, the changes with load were more subtle than a mere quantitative scaling and also seemed to be associated with a skill element in the form of variation in the duration of the phases of power production and absorption. Similarly, statistical differences (independent t-test) due to skill did not involve changes in the magnitude of power but rather the temporal organization of the movement. Thus, the ability to successfully execute the double-knee-bend movement depends on an athlete's ability to both generate a sufficient magnitude of joint power and to organize the phases of power production and absorption into an appropriate temporal sequence.
对一个典型的短时间、高功率举重项目进行了研究，以确定举起更重负荷的能力以及技能水平的差异是否伴随着下肢关节功率-时间历程特定方面的定量变化。六名有经验的举重运动员，三名技术熟练的和三名技术不太熟练的，进行了奥运会举重中提拉动作的双膝弯曲执行，该动作持续了近1秒。对三名技术熟练的受试者在举起三种负荷（其比赛最大值的69%、77%和86%）时产生的功率的选定峰值和平均值进行了方差分析统计。结果表明，技术熟练的受试者通过增加膝关节和踝关节周围的平均功率而非峰值功率来举起更重的负荷。此外，随着负荷的变化比单纯的定量缩放更为微妙，而且似乎还与功率产生和吸收阶段持续时间变化形式的技能因素有关。同样，由于技能导致的统计差异（独立t检验）并不涉及功率大小的变化，而是运动的时间组织。因此，成功执行双膝弯曲动作的能力取决于运动员产生足够大小关节功率以及将功率产生和吸收阶段组织成适当时间顺序的能力。
