MECHANICAL WORK AND EFFICIENCY IN LEVEL WALKING AND RUNNING
MECHANICAL WORK AND EFFICIENCY IN LEVEL WALKING AND RUNNING
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DOI：
10.1113/jphysiol.1977.sp011866
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发表时间：
1977-01-01
影响因子：
5.5
通讯作者：
KANEKO, M
中科院分区：
文献类型：
--
作者：
CAVAGNA, GA;KANEKO, M
在水平行走和跑步中，[在人类中]以各种恒定速度（3-33 km/h）测量了用于加速四肢相对于躯干的机械功率Wint，其中Fenn在高速跑步时使用了电影摄影程序。Wint的增加近似于步行和跑步速度的平方。对于给定的速度，步行时的Wint大于跑步时的Wint。在步行超过3公里/小时，Wint大于每一步加速和提升身体质心所花费的功率，Wext。在运行中，Wint < Wext直到约20 km/h，而在更高的速度下，Wint > Wext。正功的效率是从Wtot/净能量消耗的比率来测量的：这大于0.25，表明在步行和跑步中，肌肉在缩短期间利用了在负功（拉伸）的先前阶段期间存储的一些能量。在步行中，效率在中等速度下达到最大值（0.35-0.40），这可以从肌肉收缩成分的特性中预期。在跑步中，效率随着速度的增加而稳定地增加（从0.45到0.70-0.80），这表明正功主要来自肌肉弹性元件的被动反冲，并且在较小程度上来自收缩机械的主动缩短。这些发现与两种练习的不同机制一致。
The mechanical power spent to accelerate the limbs relative to the trunk in level walking and running, Wint, was measured [in humans] at various constant speeds (3-33 km/h) with the cinematographic procedure used by Fenn at high speeds of running. Wint increases approximately as the square of the speed of walking and running. For a given speed Wint is greater in walking than in running. In walking above 3 km/h, Wint is greater than the power spent to accelerate and lift the center of mass of the body at each step, Wext. In running Wint < Wext up to about 20 km/h, whereas at higher speeds Wint > Wext. The efficiency of positive work was measured from the ratio Wtot/Net energy expenditure: this is greater than 0.25 indicating that both in walking and in running the muscles utilize, during shortening, some energy stored during a previous phase of negative work (stretching). In walking the efficiency reaches a maximum (0.35-0.40) at intermediate speeds, as may be expected from the properties of the contractile component of muscle. In running the efficiency increases steadily with speed (from 0.45 to 0.70-0.80) suggesting that positive work derives mainly from the passive recoil of muscle elastic elements and to a lesser extent from the active shortening of the contractile machinery. These findings are consistent with the different mechanics of the 2 exercises.