MECHANICAL DETERMINANTS OF GRADIENT WALKING ENERGETICS IN MAN
MECHANICAL DETERMINANTS OF GRADIENT WALKING ENERGETICS IN MAN
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DOI：
10.1113/jphysiol.1993.sp019969
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发表时间：
1993-12-01
影响因子：
5.5
通讯作者：
SAIBENE, F
中科院分区：
文献类型：
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作者：
MINETTI, AE;ARDIGO, LP;SAIBENE, F
1.测量了四名受试者在上坡、水平和下坡步行过程中不同速度下的代谢成本和机械功。将机械功分解为因体段相对于体质心的速度变化而产生的内部功（W（int））和与体段在环境中的位置和速度变化有关的外部功（W（ext））. W（ext）进一步分为正部分（W（ext）+）和负部分（W（ext）），分别与步幅期间能量的增加和减少相关。4.对于所有恒定速度，已发现最经济的坡度为-10.2%（+/-0.8 S.D.）。5.在每个梯度上，存在唯一的W（ext）+/W（ext）-比率（在水平行走中= 1），与速度无关，W（ext）-和W（ext）+分别在+15%梯度以上和-15%梯度以下消失。W（int）在每个速度下都是常数，与梯度无关。这在一定程度上是由步幅频率在梯度增加时仅略有下降来解释的。W（int）恒定性意味着它在确定最佳梯度方面没有作用。在不同梯度下将W（ext）+和W（ext）-与代谢成本相关的线性多元回归表明，负（eff-）和正（eff+）效率随着速度的增加而降低（分别从0.912到0.726和从0.182到0.146）。然而，eff-/eff+比值保持相当恒定（4.995 +/-0.125 S.D.）。8.我们得出结论，测量的W（ext）、W（ext）+/W（ext）-分配和eff-/eff+比率，即用作力和制动发生器的肌肉的不同效率，可以解释约-10%的代谢最佳梯度。
1. The metabolic cost and the mechanical work at different speeds during uphill, level and downhill walking have been measured in four subjects.2. The mechanical work has been partitioned into the internal work (W(int)), due to the speed changes of body segment with respect to the body centre of mass (BCM), and the external work (W(ext)), related to the position and speed changes of the BCM in the environment.3. W(ext) has been further divided into a positive part (W(ext)+) and a negative one (W(ext)), associated with the energy increases and decreases, respectively, over the stride period.4. For all constant speeds the most economical gradient has been found to be -10.2% (+/- 0.8 S.D.).5. At each gradient there is a unique W(ext)+/W(ext)- ratio (= 1 in level walking), regardless of speed, with a tendency for W(ext)- and W(ext)+ to vanish above +15% and below -15% gradient, respectively.6. W(int) is constant at each speed regardless of gradient. This is partly explained by an only slight decrease in stride frequency at increasing gradient. W(int) constancy implies that it has no role in determining the optimum gradient.7. A linear multiple regression relating W(ext)+ and W(ext)-to the metabolic cost at different gradients showed that negative (eff-) and positive (eff+) efficiencies decrease with increasing speed (from 0.912 to 0.726, and from 0.182 to 0.146, respectively). The eff-/eff+ ratio, however, remains rather constant (4.995 +/-0.125 S.D.).8. We conclude that the measured W(ext), the W(ext)+/W(ext)-partitioning and eff-/eff+ ratio, i.e. the different efficiency of the muscles used as force and brake generators, can explain the metabolic optimum gradient at about -10%.