Leibniz-Institut für Arbeitsforschung an der TU Dortmund (Leibniz Research Centre for Working Environment and Human Factors), Dortmund, Germany.
Med Biol Eng Comput. 2010 Apr;48(4):361-70. doi: 10.1007/s11517-010-0585-2. Epub 2010 Feb 17.
By means of a four-degrees-of-freedom model the vertical movements of an athlete and the time course of the ground reaction force were simulated during a countermovement jump on a concrete and a wooden surface. The model masses were connected to each other and to the surface by springs and dampers. At first the stiffness of the springs decreased in order to initiate the countermovement. Afterwards the stiffness increased like the muscle activity so that the flexion of the model 'legs' were decelerated before the extension starts. The best result was attained when the stiffness of the spring between the model masses 'thighs' and 'trunk' increased before the other three springs. Compared with the muscle activity this means that for a successful jump the upper body segments have to be accelerated before the segments near to the ground are accelerated. The model 'athlete' was connected to a model of the surface. It could be shown that the jump on a concrete surface results in a better jump height than the jump on an elastic wooden surface if the muscle activation is not adapted to the surface properties.
通过一个四自由度模型，模拟了运动员在混凝土和木质表面上进行反跳时的垂直运动和地面反作用力的时程。模型质量通过弹簧和阻尼器相互连接和连接到表面。首先，弹簧的刚度减小，以启动反跳。之后，刚度增加，就像肌肉活动一样，以便在模型“腿部”伸展之前减速。当模型“大腿”和“躯干”之间的弹簧刚度在其他三个弹簧之前增加时，得到了最佳效果。与肌肉活动相比，这意味着要成功跳跃，上半身的运动必须先于靠近地面的运动。模型“运动员”连接到表面的模型。结果表明，如果肌肉激活不适应表面特性，那么在混凝土表面上跳跃比在弹性木质表面上跳跃会产生更好的跳跃高度。
