Effect of resistance taming on sympathetic nervous function in humans

抗阻训练不仅能锻炼肌肉力量，还能改善自主神经控制系统等生理功能。然而，其原理或机制尚不清楚。本项目的目的是研究运动过程中阻力训练如何影响肌肉交感神经活动（MSNA）和心血管反应。采用高强度握力训练作为抗阻训练。单侧（非优势臂）握力训练，包括3组14次的最大自主等距收缩，每组10秒，每周进行3天，持续4周。训练导致增加最大的握力在训练和未训练的手臂。研究了在训练前后以自主最大力量进行10次15秒间歇静态握力时的心率和MSNA反应。训练后，心率对握力的反应在经过训练的手臂运动和未经训练的手臂运动中都有所增加。无论训练或未训练的手臂都有更多的收缩，并且反应的开始时间比训练前早。这表明心血管和交感神经反应可能是由于在大脑高级中枢产生的中央指令，而不是肌肉反射。在前臂缺血条件下，运动后动脉闭塞2分钟，再以最大力度有节奏握拳1分钟，测试阻力训练对肌肉代谢反射的影响。虽然训练前优势臂运动比非优势臂运动有更大的代谢反射MSNA反应，但训练后训练臂（非优势臂）的MSNA反应增强，而非训练臂（对照侧）的MSNA反应没有增强，而手臂之间的反应大小没有差异。这项研究表明，抗阻训练对心率和交感神经系统有很大的影响。由此可见，即使运动过程中肌肉量很小，但强烈的运动力度对心血管系统的控制也有重要作用。少

Resistance training develops not only muscular strength but also improving physiological function such as autonomic control system. However, rationale or the mechanisms are not clear. A goal of this project was to investigate how resistance-training influence muscle sympathetic nerve activity (MSNA) and cardiovascular response during exercise.High intensity handgrip exercise was used as resistance training. Unilateral (nondominant arm) handgrip training, which composed 3 set of 14 times of 10-sec maximal voluntary isometric contraction, was performed three days per week for 4 weeks. The training lead to increased maximal handgrip force in trained as well as untrained arm.Heart rate and MSNA response during 10 times intermittent static handgrip for 15 seconds performed with voluntary maximum effort was investigated before and after training. After training heart rate response to the handgrip increased for trained arm exercise and also for untrained arm exercise. MSNA was increased durin … More g contractions of either trained or untrained arm and the onset of the response was earlier than that before training. This suggests that cardiovascular and sympathetic nervous response may be due to central command that was generated in the higher brain center rather than muscle reflex.Effect of resistance training on muscle metaboreflex was tested during two minutes post exercise arterial occlusion followed rhythmic handgrip for one minute performed with maximal effort under the forearm ischemia. Although before training dominant arm exercise had a greater metaboreflex MSNA response than that of nondominant armor The MSNA response for trained arm (nondominant arm), but not untrained arm (control side) enhanced after training, while the size of response was not different between the arms.This study demonstrated that resistance training have great effect on heart rate and sympathetic nervous system. From these results suggest that strong exercise effort even if active muscle mass was small involved during exercise play an important role to cardiovascular control system. Less