SOURCES OF EXTERNAL WORK IN LEVEL WALKING AND RUNNING
SOURCES OF EXTERNAL WORK IN LEVEL WALKING AND RUNNING
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DOI：
10.1113/jphysiol.1976.sp011613
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发表时间：
1976-01-01
影响因子：
5.5
通讯作者：
ZAMBONI, A
中科院分区：
文献类型：
--
作者：
CAVAGNA, GA;THYS, H;ZAMBONI, A
在水平行走和跑步过程中，为了提升身体的质心Wv，增加身体的前进速度Wf，以及所涉及的总机械能（势能+动能）Wext，在每一步所做的功已经用Cavagna（1975）描述的技术在各种"恒定"速度（2 - 32 km/hr）下测量。2.在中等步行速度（约4km/hr）下，Wv = Wf，并且Wext/km最小，能量成本也最小。在较低的速度下，Wv大于Wf，而在较高的速度下，Wf大于Wv：在这两种情况下，Wext/km增加。3.通过步行的摆动运动特性，机械能的恢复被测量为（/Wv/+/Wf/-Wext）/（/Wv/+/Wf/）：在中等速度下达到最大值（约65%）。4.一个简单的模型，假设在行走时，身体像倒立摆一样在与地面接触的脚上旋转，在中等速度下更好地拟合实验数据，但在7公里/小时以上不再成立。5.在跑步中，上述定义的恢复是最小的（0 - 4%，与速度无关），即Wext与/Wv/+/Wf/一致：身体的势能和动能不交换，但同时被肌肉吸收和释放，其速率随速度显著增加（约1至4 h. p.）。6.由于Wv实际上是与Vf无关的常数，因此Wext从正的y截距随着运行速度Vf线性地增加。相反，Wf = aVf 2/（1 + bVf），其中B是在空中花费的时间与在地面上时在每一步期间所覆盖的向前距离之间的比率。
The work done at each step during level walking and running to lift the centre of mass of the body, Wv, and to increase its forward speed, Wf, and the total mechanical energy involved (potential + kinetic) Wext, have been measured at various 'constant' speeds (2‐32 km/hr) with the technique described by Cavagna (1975). 2. At intermediate speeds of walking (about 4 km/hr) Wv = Wf and Wext/km is at a minimum, as is the energy cost. At lower speeds Wv greater than Wf whereas at higher speeds Wf greather than Wv: in both cases Wext/km increases. 3. The recovery of mechanical energy, through the pendular motion characteristic of walking, was measured as (/Wv/ + /Wf/ ‐ Wext)/(/Wv/ + /Wf/): it attains a maximum (about 65%) at intermediate speeds. 4. A simple model, assuming that in walking the body rotates as an inverted pendulum over the foot in contact with the ground, fits the experimental data better at intermediate speeds but is no longer tenable above 7 km/hr. 5. In running the recovery defined above is minimal (0‐4% independent of speed), i.e. Wext congruent to /Wv/ + /Wf/: potential and kinetic energy of the body do not interchange but are simultaneously taken up and released by the muscles with a rate increasing markedly with the speed (from about 1 to 4 h.p.). 6. Wext increases linearly with the running speed Vf from a positive y intercept owing to the fact that Wv is practically constant independent of Vf. On the contrary, Wf = aVf2/(1 + bVf), where b is the ratio between the time spent in the air and the forward distance covered while on the ground during each step.