Alexander R M
Department of Pure and Applied Biology, University of Leeds, U.K.
Philos Trans R Soc Lond B Biol Sci. 1992 Oct 29;338(1284):189-98. doi: 10.1098/rstb.1992.0138.
Simple mathematical models capable of walking or running are used to compare the merits of bipedal gaits. Stride length, duty factor (the fraction of the stride, for which the foot is on the ground) and the pattern of force on the ground are varied, and the optimum gait is deemed to be the one that minimizes the positive work that the muscles must perform, per unit distance travelled. Even the simplest model, whose legs have neither mass nor elastic compliance, predicts the changes of duty factor and force pattern that people make as they increase their speed of walking. It predicts a sudden change to running at a critical speed, but this is much faster than the speed at which people make the change. When elastic compliance is incorporated in the model, unnaturally fast walking becomes uncompetitive. However, a slow run with very brief foot contact becomes the optimum gait at low speeds, at which people would walk, unless severe energy dissipation occurs in the compliance. A model whose legs have mass as well as elastic compliance predicts well the relationship between speed and stride length in human walking.
能够行走或奔跑的简单数学模型被用于比较双足步态的优点。步长、 Duty 系数（即脚着地的步幅比例）以及地面受力模式会发生变化，而最佳步态被认为是在单位行进距离内使肌肉必须执行的正功最小化的步态。即使是最简单的模型，其腿部既无质量也无弹性顺应性，也能预测人们在加快步行速度时 Duty 系数和受力模式的变化。它预测在临界速度时会突然转变为奔跑，但这比人们实际转变的速度要快得多。当模型纳入弹性顺应性时，不自然的快速行走就变得缺乏竞争力。然而，在低速时，脚接触时间非常短的慢跑成为最佳步态，在这种速度下人们通常会行走，除非在顺应性过程中发生严重的能量耗散。一个腿部既有质量又有弹性顺应性的模型能很好地预测人类行走中速度与步长之间的关系。
