Dech Silas, Bittmann Frank N, Schaefer Laura V
Devision of Regulative Physiology and Prevention, Department of Sports and Health Sciences, University of Potsdam, 14476 Potsdam, Germany.
Diagnostics (Basel). 2021 Oct 23;11(11):1973. doi: 10.3390/diagnostics11111973.
The regulation of oxygen and blood supply during isometric muscle actions is still unclear. Recently, two behavioral types of oxygen saturation (SvO) and relative hemoglobin amount (rHb) in venous microvessels were described during a fatiguing holding isometric muscle action (HIMA) (type I: nearly parallel behavior of SvO and rHb; type II: partly inverse behavior). The study aimed to ascertain an explanation of these two regulative behaviors. Twelve subjects performed one fatiguing HIMA trial with each arm by weight holding at 60% of the maximal voluntary isometric contraction (MVIC) in a 90° elbow flexion. Six subjects additionally executed one fatiguing PIMA trial by pulling on an immovable resistance with 60% of the MVIC with each side and same position. Both regulative types mentioned were found during HIMA (I: = 7, II: = 17) and PIMA (I: = 3, II: = 9). During the fatiguing measurements, rHb decreased initially and started to increase in type II at an average SvO-level of 58.75 ± 2.14%. In type I, SvO never reached that specific value during loading. This might indicate the existence of a threshold around 59% which seems to trigger the increase in rHb and could explain the two behavioral types. An approach is discussed to meet the apparent incompatibility of an increased capillary blood filling (rHb) despite high intramuscular pressures which were found by other research groups during isometric muscle actions.
在等长肌肉运动过程中，氧气和血液供应的调节机制仍不清楚。最近，在疲劳性等长肌肉运动（HIMA）过程中，描述了静脉微血管中两种行为类型的氧饱和度（SvO）和相对血红蛋白量（rHb）（I型：SvO和rHb几乎平行的行为；II型：部分相反的行为）。该研究旨在确定对这两种调节行为的解释。12名受试者通过在90°肘部弯曲时以最大自主等长收缩（MVIC）的60%进行负重，对每只手臂进行一次疲劳性HIMA试验。另外6名受试者通过在相同位置以MVIC的60%拉动固定阻力，对每一侧进行一次疲劳性PIMA试验。在HIMA（I型：n = 7，II型：n = 17）和PIMA（I型：n = 3，II型：n = 9）过程中均发现了上述两种调节类型。在疲劳测量过程中，rHb最初下降，在II型中，当平均SvO水平为58.75±2.14%时开始增加。在I型中，SvO在负荷期间从未达到该特定值。这可能表明存在一个约59%的阈值，该阈值似乎触发了rHb的增加，并可以解释这两种行为类型。讨论了一种方法，以解决尽管在等长肌肉运动过程中其他研究小组发现肌肉内压力较高，但毛细血管血液充盈（rHb）增加这一明显的不兼容性问题。
