Exercise Physiology Laboratory, Department of Nutrition and Health Sciences, University of Nebraska-Lincoln, Lincoln, Nebraska; and.
Department of Health and Human Performance, University of Wisconsin-Platteville, Platteville, Wisconsin.
J Strength Cond Res. 2024 May 1;38(5):e219-e225. doi: 10.1519/JSC.0000000000004730.
Ortega, DG, Housh, TJ, Smith, RW, Arnett, JE, Neltner, TJ, Schmidt, RJ, and Johnson, GO. The effects of anchoring a fatiguing forearm flexion task to a high versus low rating of perceived exertion on torque and neuromuscular responses. J Strength Cond Res 38(5): e219-e225, 2024-This study examined the torque and neuromuscular responses following sustained, isometric, forearm flexion tasks anchored to 2 ratings of perceived exertion (RPE). Nine men (mean ± SD: age = 21.0 ± 2.4 years; height = 179.5 ± 5.1 cm; body mass = 79.6 ± 11.4 kg) completed maximal voluntary isometric contractions (MVIC) before and after sustained, isometric, forearm flexion tasks to failure anchored to RPE = 2 and RPE = 8. The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) signal were recorded from the biceps brachii. Normalized torque was divided by normalized EMG AMP to calculate neuromuscular efficiency (NME). A dependent t-test was used to assess the mean difference for time to task failure (TTF). Repeated-measures analysis of variances was used to compare mean differences for MVIC and normalized neuromuscular parameters. There was no significant difference in TTF between RPE = 2 and RPE = 8 (p = 0.713). The MVIC decreased from pretest to posttest at RPE = 2 (p = 0.009) and RPE = 8 (p = 0.003), and posttest MVIC at RPE = 8 was less than that at RPE = 2 (p < 0.001). In addition, NME decreased from pretest to posttest (p = 0.008). There was no change in normalized EMG AMP or EMG MPF (p > 0.05). The current findings indicated that torque responses were intensity specific, but TTF and neuromuscular responses were not. Furthermore, normalized EMG AMP and EMG MPF remained unchanged but NME decreased, likely due to peripheral fatigue and excitation-contraction coupling failure. Thus, this study provides information regarding the neuromuscular responses and mechanisms of fatigue associated with tasks anchored to RPE, which adds to the foundational understanding of the relationship between resistance exercise and the perception of fatigue.
奥尔蒂斯、DG、豪什、TJ、史密斯、RW、阿内特、JE、内尔特纳、TJ、施密特、RJ 和约翰逊，GO。将疲劳的前臂弯曲任务固定在感知用力程度的高与低评分上，对扭矩和神经肌肉反应的影响。J 强能力研究 38(5)：e219-e225，2024-本研究考察了固定在 2 个感知用力程度评分（RPE）的持续等长前臂弯曲任务后的扭矩和神经肌肉反应。9 名男性（平均±SD：年龄=21.0±2.4 岁；身高=179.5±5.1cm；体重=79.6±11.4kg）在持续等长前臂弯曲任务至力竭之前完成了最大自主等长收缩（MVIC），这些任务固定在 RPE=2 和 RPE=8。从肱二头肌记录肌电图（EMG）信号的幅度（AMP）和平均功率频率（MPF）。将归一化扭矩除以归一化 EMG AMP 以计算神经肌肉效率（NME）。使用依赖 t 检验评估任务失败时间（TTF）的平均差异。使用重复测量方差分析比较 MVIC 和归一化神经肌肉参数的平均差异。RPE=2 和 RPE=8 之间的 TTF 无显著差异（p=0.713）。MVIC 在 RPE=2（p=0.009）和 RPE=8（p=0.003）时从预测试到后测试均降低，且 RPE=8 的后测试 MVIC 小于 RPE=2（p<0.001）。此外，NME 从预测试到后测试降低（p=0.008）。归一化 EMG AMP 或 EMG MPF 无变化（p>0.05）。当前的研究结果表明，扭矩反应具有强度特异性，但 TTF 和神经肌肉反应没有。此外，归一化 EMG AMP 和 EMG MPF 保持不变，但 NME 降低，可能是由于外周疲劳和兴奋-收缩耦联失败。因此，本研究提供了有关与 RPE 相关的任务的神经肌肉反应和疲劳机制的信息，这增加了对阻力运动与疲劳感知之间关系的基础理解。
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