Several studies have used transcranial magnetic stimulation to probe the corticospinal-motoneuronal responses to a single session of strength training; however, the findings are inconsistent. This systematic review and meta-analysis examined whether a single bout of strength training affects the excitability and inhibition of intracortical circuits of the primary motor cortex (M1) and the corticospinal-motoneuronal pathway. A systematic review was completed, tracking studies between January 1990 and May 2018. The methodological quality of studies was determined using the Downs and Black quality index. Data were synthesised and interpreted from meta-analysis. Nine studies (n=107) investigating the acute corticospinal-motoneuronal responses to strength training met the inclusion criteria. Meta-analyses detected that after strength training compared to control, corticospinal excitability [standardised mean difference (SMD), 1.26; 95% confidence interval (CI), 0.88, 1.63; p<0.0001] and intracortical facilitation (ICF) (SMD, 1.60; 95% CI, 0.18, 3.02; p=0.003) were increased. The duration of the corticospinal silent period was reduced (SMD, −17.57; 95% CI, −21.12, −14.01; p=0.00001), but strength training had no effect on the excitability of the intracortical inhibitory circuits [short-interval intracortical inhibition (SICI) SMD, 1.01; 95% CI, −1.67, 3.69; p=0.46; long-interval intracortical inhibition (LICI) SMD, 0.50; 95% CI, −1.13, 2.13; p=0.55]. Strength training increased the excitability of corticospinal axons (SMD, 4.47; 95% CI, 3.45, 5.49; p<0.0001). This systematic review and meta-analyses revealed that the acute neural changes to strength training involve subtle changes along the entire neuroaxis from the M1 to the spinal cord. These findings suggest that strength training is a clinically useful tool to modulate intracortical circuits involved in motor control.

中文翻译：

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确定早期皮质脊髓运动神经元对力量训练的反应：系统评价和荟萃分析

一些研究使用经颅磁刺激来探测皮质脊髓运动神经元对单次力量训练的反应。然而，调查结果并不一致。这项系统评价和荟萃分析检查了单次力量训练是否会影响初级运动皮层 (M1) 和皮质脊髓运动神经元通路的皮质内回路的兴奋性和抑制性。完成了一项系统评价，追踪了 1990 年 1 月至 2018 年 5 月之间的研究。研究的方法学质量由 Downs 和 Black 质量指数确定。从荟萃分析中综合和解释数据。九项研究 (n=107) 调查了对力量训练的急性皮质脊髓运动神经元反应，符合纳入标准。荟萃分析发现，与对照组相比，在力量训练后，皮质脊髓兴奋性 [标准化平均差 (SMD)，1.26；95% 置信区间 (CI), 0.88, 1.63;p<0.0001] 和皮质内促进 (ICF) (SMD, 1.60; 95% CI, 0.18, 3.02;p=0.003) 增加。皮质脊髓静默期的持续时间缩短（SMD，-17.57；95% CI，-21.12，-14.01；p= 0.00001），但力量训练对皮质内抑制回路的兴奋性没有影响[短间隔皮质内抑制（SICI）SMD，1.01；95% CI, -1.67, 3.69;p=0.46; 长间隔皮质内抑制 (LICI) SMD，0.50；95% CI, -1.13, 2.13;p=0.55]。力量训练增加了皮质脊髓轴突的兴奋性（SMD, 4.47; 95% CI, 3.45, 5.49;p<0.0001)。这项系统回顾和荟萃分析表明，力量训练的急性神经变化涉及从 M1 到脊髓的整个神经轴的细微变化。这些发现表明，力量训练是一种临床上有用的工具，可以调节参与运动控制的皮层内回路。