Legrand Renaud, Marles Alexandre, Prieur Fabrice, Lazzari Stefano, Blondel Nicolas, Mucci Patrick
Laboratory of Human Movement Studies, Faculty of Sports Sciences and Physical Education, Lille University, Lille, France.
Med Sci Sports Exerc. 2007 Jan;39(1):91-100. doi: 10.1249/01.mss.0000241638.90348.67.
We investigated the potential effect of respiratory muscle work on leg muscle oxygenation without artificial intervention in non-endurance-trained young subjects and searched for the range of intensity when this effect could occur.
We simultaneously monitored accessory respiratory and leg muscle oxygenation patterns with near-infrared spectroscopy (NIRS) in 15 healthy young men performing maximal incremental exercise on a cycle ergometer. Pulmonary gas exchange was measured. The respiratory compensation point (RCP) was determined. Oxygenation (RMO2) and blood volume (RMBV) of the serratus anterior (accessory respiratory muscle) and of the vastus lateralis (LegO2 and LegBV) were monitored with NIRS. The breakdown point of accessory respiratory muscle oxygenation (BPRMO2) and the accelerated (BP1LegO2) and attenuated fall (BP2LegO2) in leg muscle oxygenation were detected.
BPRMO2 occurred at approximately 85% .VO2max and was related to RCP (r = 0.88, P < 0.001). BP2LegO2 appeared at approximately 83% .VO2max and was related to RCP (r = 0.57, P < 0.05) and with BPRMO2 (r = 0.64, P = 0.01). From BP2LegO2 to maximal exercise, LegBV was significantly reduced (P < 0.05).
In active subjects exercising at heavy exercise intensities, we observed that the appearance of the accelerated drop in accessory respiratory muscle oxygenation-associated with high ventilatory level-was related with the attenuated fall in leg muscle oxygenation detected with near-infrared spectroscopy. This suggests that the high oxygen requirement of respiratory muscle leads to limited oxygen use by locomotor muscles as demonstrated in endurance-trained subjects. The phenomenon observed was associated with reduced leg blood volume, supporting the occurrence of leg vasoconstriction. These events appeared not only at maximal exercise but onward above the respiratory compensation point.
我们在未经耐力训练的年轻受试者中，研究了呼吸肌工作对腿部肌肉氧合的潜在影响，且未进行人工干预，并探寻这种影响可能发生的强度范围。
我们使用近红外光谱（NIRS），同时监测了15名健康年轻男性在自行车测力计上进行最大递增运动时辅助呼吸肌和腿部肌肉的氧合模式。测量了肺气体交换。确定了呼吸补偿点（RCP）。用NIRS监测前锯肌（辅助呼吸肌）和股外侧肌（LegO2和LegBV）的氧合（RMO2）和血容量（RMBV）。检测了辅助呼吸肌氧合的临界点（BPRMO2）以及腿部肌肉氧合的加速下降点（BP1LegO2）和衰减下降点（BP2LegO2）。
BPRMO2出现在约85%最大摄氧量时，且与RCP相关（r = 0.88，P < 0.001）。BP2LegO2出现在约83%最大摄氧量时，且与RCP相关（r = 0.57，P < 0.05），并与BPRMO2相关（r = 0.64，P = 0.01）。从BP2LegO2到最大运动，LegBV显著降低（P < 0.05）。
在进行高强度运动的活跃受试者中，我们观察到与高通气水平相关的辅助呼吸肌氧合加速下降的出现，与用近红外光谱检测到的腿部肌肉氧合衰减下降有关。这表明呼吸肌的高氧需求导致运动肌肉的氧利用受限，正如耐力训练受试者所表现的那样。观察到的现象与腿部血容量减少有关，支持腿部血管收缩的发生。这些情况不仅出现在最大运动时，而且在呼吸补偿点以上就已出现。
