Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.
Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.
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DOI：
10.1371/journal.pone.0168517
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Fukuba Y
中科院分区：
文献类型：
--
作者：
Fukuoka Y;Iihoshi M;Nazunin JT;Abe D;Fukuba Y
我们的研究调查了在两种运动的代谢需求相同的情况下，呼吸和气体交换反应是否表现出不同的动力学反应，以响应循环作业率或步行速度的正弦变化。测定了10名健康青年受试者的运动参数(步长和步频)、呼吸通气量(V̇E)和气体交换(CO_2排出量(V̇CO_2)和氧气摄取量(V̇O_2))反应。跑步机的速度在3~6 km·h-1之间呈正弦变化，并有不同的周期(10~1min)。机车参数对正弦变化的幅值具有恒定的增益和较小的相移，与振荡周期无关。当速度振荡周期缩短时，V̇E的幅度急剧减小，而V̇E的相移增大。在同等代谢需求下步行与骑行比较，正弦步行(Sw)时V-̇E波幅明显大于正弦周期(SC)，相移变小。SW组V̇E波幅比V̇CO_2波幅比的线性回归斜率比SC组大。这些结果表明，即使两种运动的代谢需求相等，但呼吸动力学的大幅度和小相移并不等同于西南和SC。这种现象可能源于中枢指令与运动肌招募(前馈)和肌肉传入反馈成比例。
Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency), breath-by-breath ventilation (V̇E) and gas exchange (CO2 output (V̇CO2) and O2 uptake (V̇O2)) responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min). The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW) was significantly greater than that during sinusoidal cycling (SC), and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward) and muscle afferent feedback.