Discipline of Physiology & Health, Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, UNITED KINGDOM.
Med Sci Sports Exerc. 2017 Oct;49(10):2025-2031. doi: 10.1249/MSS.0000000000001326.
To improve the current understanding of the impact of resistance exercise on the heart, by examining the acute responses of left ventricular (LV) strain, twist, and untwisting rate ("LV mechanics").
LV echocardiographic images were recorded in systole and diastole before, during and immediately after (7-12 s) double-leg press exercise at two intensities (30% and 60% of maximum strength, one-repetition maximum). Speckle tracking analysis generated LV strain, twist, and untwisting rate data. Additionally, beat-by-beat blood pressure was recorded and systemic vascular resistance (SVR) and LV wall stress were calculated.
Responses in both exercise trials were statistically similar (P > 0.05). During effort, stroke volume decreased, whereas SVR and LV wall stress increased (P < 0.05). Immediately after effort, stroke volume returned to baseline, whereas SVR and wall stress decreased (P < 0.05). Similarly, acute exercise was accompanied by a significant decrease in systolic parameters of LV muscle mechanics (P < 0.05). However, diastolic parameters, including LV untwisting rate, were statistically unaltered (P > 0.05). Immediately after exercise, systolic LV mechanics returned to baseline levels (P < 0.05) but LV untwisting rate increased significantly (P < 0.05).
A single, acute bout of double-leg press resistance exercise transiently reduces systolic LV mechanics, but increases diastolic mechanics after exercise, suggesting that resistance exercise has a differential impact on systolic and diastolic heart muscle function. The findings may explain why acute resistance exercise has been associated with reduced stroke volume but chronic exercise training may result in increased LV volumes.
通过检查左心室（LV）应变、扭转和扭转率的急性反应（“LV 力学”），提高对阻力运动对心脏影响的现有认识。
在以 30%和 60%最大强度（一次重复最大值）的双腿按压运动前、运动中和运动后立即（7-12 秒）记录收缩期和舒张期的 LV 超声心动图图像。斑点跟踪分析生成 LV 应变、扭转和扭转率数据。此外，记录逐搏血压并计算全身血管阻力（SVR）和 LV 壁应力。
两种运动试验的反应在统计学上相似（P>0.05）。在努力过程中，心输出量减少，而 SVR 和 LV 壁应力增加（P<0.05）。运动后立即，心输出量恢复到基线，而 SVR 和壁应力降低（P<0.05）。同样，急性运动伴随着 LV 肌肉力学的收缩期参数显著下降（P<0.05）。然而，舒张期参数，包括 LV 扭转率，在统计学上没有改变（P>0.05）。运动后立即，LV 力学的收缩期参数恢复到基线水平（P<0.05），但 LV 扭转率显著增加（P<0.05）。
单次急性双腿按压阻力运动短暂降低收缩期 LV 力学，但运动后增加舒张期力学，这表明阻力运动对收缩期和舒张期心肌功能有不同的影响。研究结果可能解释了为什么急性阻力运动与心输出量减少有关，而慢性运动训练可能导致 LV 容积增加。
