The influence of circulatory difference on muscle oxygenation and fatigue during intermittent static dorsiflexion
The influence of circulatory difference on muscle oxygenation and fatigue during intermittent static dorsiflexion
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DOI：
10.1007/s00421-003-1024-y
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发表时间：
2004-05-01
影响因子：
3
通讯作者：
Fukunaga, T
中科院分区：
文献类型：
--
作者：
Tachi, M;Kouzaki, M;Fukunaga, T
本研究旨在探讨背屈运动中，不同体位下循环差异对胫骨前肌（TA）氧利用率和疲劳进程的影响。受试者以最大随意收缩（MVC）的50%进行间歇性静态背屈，直到右腿相对于心脏向上或向下。这些练习在有或没有阻塞肌肉血流的情况下进行。在表面肌电图（EMG）测量的同时，用近红外光谱（NIRS）测量TA的总血红蛋白体积变化和组织氧合（StO 2）。当受试者以50%MVC进行力竭性间歇背屈运动时，腿向上位置的耐力时间减少。此外，使用EMG信号（即积分EMG和EMG的平均功率频率）检测的TA中的疲劳的进展随着腿抬高而更快。近红外光谱数据表明，较低的血容量和StO 2与腿在运动过程中，这表明在O-2供应的不足，以运动肌肉的需求是更明显的腿上的位置。然而，当血流在两个位置都受到限制时，EMG和NIRS数据的这些差异消失。从这些结果可以得出结论，两种不同的身体姿势之间的运动肌肉氧合的差异影响肌肉疲劳的进展，并导致耐力表现的差异。
This study aimed to examine the influences of circulatory difference on the utilization of O-2 and the progression of fatigue in the tibialis anterior (TA) muscle during dorsiflexion exercise, with reference to different body postures. The subjects performed intermittent static dorsiflexion at 50% of maximal voluntary contraction (MVC) up to exhaustion with the right leg either up or down relative to the heart. These exercises were performed with and without occluding muscle blood flow. Simultaneously with the surface electromyogram (EMG) measurement, total hemoglobin volume change and tissue oxygenation (StO2) of TA were measured using near-infrared spectroscopy (NIRS). When the subjects performed an exhaustive intermittent dorsiflexion exercise at 50% MVC, the endurance time decreased in the leg up position. Also, the progression of fatigue in TA detected using EMG signals (i.e. integrated EMG and mean power frequency of EMG) was faster with the leg elevated. The NIRS data indicated a lower blood volume and StO2 with the leg up than with the leg down during the exercise, which suggests that the deficit in the O-2 supply to exercising muscle's demand was more apparent in the leg up position. However, these differences in EMG and NIRS data disappeared when the blood flow was restricted in both positions. From these results it is concluded that the difference in exercising muscle oxygenation between two different body postures influenced the progression of muscle fatigue and caused the difference in endurance performance.