Department of Ischemic Circulatory Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Metabolism. 2010 Oct;59(10):1510-9. doi: 10.1016/j.metabol.2010.01.016. Epub 2010 Mar 4.
The effect of low-intensity resistance exercise with external limb compression (100 [EC100] and 160 [EC160] mm Hg) on limb blood flow and venous blood gas-metabolite response was investigated and compared with that of high-intensity resistance exercise (no external compression). Unilateral elbow flexion muscle contractions were performed at 20% (75 repetitions, 4 sets, 30-second rest intervals) and 70% of 1-repetition maximum (1-RM; 3 sets, each set was until failure, 3-minute rest intervals). Precontraction brachial arterial blood flow (Doppler ultrasound) was reduced with EC100 or EC160 (56% and 39% of baseline value, respectively) compared with no external compression (control). At 20% 1-RM, brachial arterial blood flow increased after contractions performed with EC160 (190%), but not with the others. Decreases in venous oxygen partial pressure (P(v)O(2)) and venous oxygen saturation (S(v)O(2)) were greater during EC100 and EC160 than control (mean [SE]: P(v)O(2), 28 [3] vs 26 [2] vs 33 [2] mm Hg; S(v)O(2), 41% [5%] vs 34% [4%] vs 52% [5%], respectively). Changes in venous pH (pH(v)), venous carbon dioxide partial pressure (P(v)CO(2)), and venous lactate concentration (L(-)) were greater with EC160 than EC100 and/or control (pH(v), 7.19 [0.01] vs 7.25 [0.01] vs 7.27 [0.02]; P(v)CO(2), 72 [3] vs 64 [2] vs 60 [3] mm Hg; L(-), 5.4 [0.6] vs 3.7 [0.4] vs 3.0 [0.4] mmol/L, respectively). Seventy percent 1-RM contractions resulted in greater changes in pH(v) (7.14 [0.02]), P(v)CO(2) (91 [5] mm Hg), and L(-) (7.0 [0.5] mmol/L) than EC100 and EC160, but P(v)O(2) (30 [4] mm Hg) and S(v)O(2) (40% [3%]) were similar. In conclusion, changes in pH(v), P(v)CO(2), and L(-), but not in P(v)O(2) and S(v)O(2), are sensitive to changes in relative, "internal" intensity of low-intensity muscle contractions caused by reduced blood flow (EC160) or high-intensity muscle contractions. Given the magnitude of the changes in pH(v), P(v)CO(2), and L(-), it appears plausible that they may be involved in stimulating the observed increase in muscle activation via group III and IV afferents.
研究了低强度抗阻运动（外部肢体压缩 100[EC100] 和 160[EC160]mmHg）和高强度抗阻运动（无外部压缩）对肢体血流和静脉血气代谢产物的影响，并进行了比较。在 20%（75 次重复，4 组，30 秒休息间隔）和 70%的 1 次重复最大强度（1-RM；3 组，每组直至力竭，3 分钟休息间隔）下进行单侧肘部弯曲肌肉收缩。与无外部压缩（对照）相比，EC100 或 EC160 降低了预收缩肱动脉血流（多普勒超声）（分别为基线值的 56%和 39%）。在 20%的 1-RM 时，EC160 收缩后肱动脉血流增加（增加 190%），而其他组则没有。与对照相比，EC100 和 EC160 时静脉氧分压（P(v)O(2)）和静脉血氧饱和度（S(v)O(2)）的下降更大（平均值[SE]：P(v)O(2)，28[3] vs 26[2] vs 33[2]mmHg；S(v)O(2)，41%[5%] vs 34%[4%] vs 52%[5%]）。与 EC100 和/或对照相比，EC160 时静脉 pH（pH(v)）、静脉二氧化碳分压（P(v)CO(2)）和静脉乳酸浓度(L(-))的变化更大（pH(v)，7.19[0.01] vs 7.25[0.01] vs 7.27[0.02]；P(v)CO(2)，72[3] vs 64[2] vs 60[3]mmHg；L(-)，5.4[0.6] vs 3.7[0.4] vs 3.0[0.4]mmol/L）。70%的 1-RM 收缩导致 pH(v)（7.14[0.02]）、P(v)CO(2)（91[5]mmHg）和L(-)（7.0[0.5]mmol/L）的变化大于 EC100 和 EC160，但 P(v)O(2)（30[4]mmHg）和 S(v)O(2)（40%[3%]）相似。结论：与相对“内部”血流减少（EC160）或高强度肌肉收缩引起的低强度肌肉收缩的相对强度变化相关的 pH(v)、P(v)CO(2)和L(-)的变化敏感，但 P(v)O(2)和 S(v)O(2)则不然。考虑到 pH(v)、P(v)CO(2)和L(-)的变化幅度，似乎可以推测它们可能通过 III 类和 IV 类传入纤维参与刺激观察到的肌肉激活增加。
