Minetti A E, Capelli C, Zamparo P, di Prampero P E, Saibene F
Istituto Tecnologie Biomediche Avanzate, Consiglio Nazionale delle Ricerche, Milano, Italy.
Med Sci Sports Exerc. 1995 Aug;27(8):1194-202.
The energetics and mechanics of walking were investigated at different speeds, both at the freely chosen stride frequency (FCSF) and at imposed ones (up to +/- 40% of FCSF). Metabolic energy expenditure was minimized at FCSF for each speed. Motion analysis allowed to calculate: the mechanical internal work rate (Wint), needed to move the segments with respect to the body center of mass (bcm); the external work rate (Wext), necessary to move bcm in the environment; and the total work rate (Wtot), equal to Wint+Wext. Wtot explains the metabolic optimization only at high speeds, while Wext, differently from previously reported, displays minima which better predict FCSF at all speeds (exception made for 1.39 m.s-1). This is probably caused by an overestimation of Wint due to a more ballistic movement of the limbs at low speeds (and low frequencies). The tendency of Wext to increase at high frequencies is due to a persistent minimal vertical excursion of bcm (about 0.02 m, the "locomotory dead space"). While the match between mechanics and energetics (at FCSF and imposed frequencies) occurs to a certain extent, it could be improved by removing the methodological assumptions about the energy transfer between segments and by the possibility to account for the coactivation of antagonist muscles.
研究了不同速度下行走的能量学和力学，包括自由选择的步频（FCSF）以及施加的步频（高达FCSF的±40%）。在每个速度下，代谢能量消耗在FCSF时最小。运动分析能够计算：使各节段相对于身体质心（bcm）移动所需的机械内部功率（Wint）；在环境中移动bcm所需的外部功率（Wext）；以及总功率（Wtot），其等于Wint + Wext。Wtot仅在高速时能解释代谢优化情况，而与先前报道不同的是，Wext呈现出最小值，能在所有速度下（1.39 m·s-1除外）更好地预测FCSF。这可能是由于低速（和低频）时肢体运动更具弹道性导致Wint被高估。Wext在高频时增加的趋势是由于bcm持续保持最小垂直偏移（约0.02 m，即“运动死区”）。虽然力学和能量学之间（在FCSF和施加频率下）在一定程度上存在匹配，但通过消除关于节段间能量传递的方法学假设以及考虑拮抗肌的共同激活，这种匹配情况可能会得到改善。
