Department of Kinesiology and Health Promotion, The University of Kentucky, Lexington, Kentucky.
J Strength Cond Res. 2024 Aug 1;38(8):e405-e416. doi: 10.1519/JSC.0000000000004812.
Kwak, M, Succi, PJ, Benitez, B, Mitchinson, C, Samaan, MA, Abel, MG, and Bergstrom, HC. Comparison of force, neuromuscular, and metabolic responses during sustained, isometric handgrip holds to failure anchored to low and high perceptual intensities in men: An exploratory study. J Strength Cond Res 38(8): e405-e416, 2024-This study examined the responses of force alterations, relative to critical force (CF), neuromuscular parameters, and muscle oxygenation (SmO2) for isometric handgrip holds to failure (HTF) anchored to ratings of perceived exertion (RPE) of 3 and 7. Twelve men completed pre-maximal voluntary isometric contractions (pre-MVIC), submaximal HTF at 4 percentages of pre-MVIC, HTF at RPE = 3 and 7, and post-MVIC. Mechanomyograpic (MMG) signals and SmO2 were recorded during the RPE HTF. Analyses included paired-samples t-tests and repeated-measures ANOVAs at an alpha level of p ≤ 0.05. Time to task failure was not different between RPE 3 (478.7 ± 196.6 s) and RPE 7 (495.8 ± 173.8 s). Performance fatigability (PF) and MMG amplitude (AMP) were greater for RPE 7 (PF: 37.9 ± 12.9%; MMG AMP: 15.7 ± 7.4% MVIC) than RPE 3 (PF: 30.0 ± 14.5%; MMG AMP: 10.2 ± 6.5% MVIC), but MMG mean power frequency (MPF) was greater for RPE 3 (146.2 ± 31.1% MVIC) than RPE 7 (128.8 ± 23.0% MVIC). There were RPE-dependent decreases in force (p ≤ 0.01) across 3 discernable phases during the HTF. There were decreases in MMG AMP across time for both RPEs, but there were no significant changes in MMG MPF or SmO2. There were overall similar motor unit control strategies and local metabolic demand between RPEs. The majority of the HTF performed below CF at RPE 3 and 7 indicated CF did not reflect the highest sustainable force. When prescribing isometric exercise anchored to RPE, practitioners should be aware of the magnitude of force loss and relative intensity of the task to be sure desired training loads are met.
Kwak, M, Succi, PJ, Benitez, B, Mitchinson, C, Samaan, MA, Abel, MG, 和 Bergstrom, HC。比较男子在低和高感知强度下进行持续等长握力至力竭时的力、神经肌肉和代谢反应：一项探索性研究。J 力量与调理研究 38(8): e405-e416, 2024- 本研究检查了等长握力至力竭（HTF）锚定在 3 和 7 的感觉用力评估（RPE）时力的变化、相对临界力（CF）、神经肌肉参数和肌肉氧合（SmO2）的反应。12 名男性完成了最大预收缩等长收缩（pre-MVIC）、4% pre-MVIC 的亚最大 HTF、RPE=3 和 7 的 HTF 以及 post-MVIC。在 RPE HTF 期间记录肌电描记术（MMG）信号和 SmO2。分析包括配对样本 t 检验和重复测量方差分析，置信水平为 p≤0.05。RPE 为 3（478.7±196.6 s）和 RPE 为 7（495.8±173.8 s）时，达到任务失败的时间没有差异。RPE 7 的疲劳性（PF）和 MMG 振幅（AMP）（PF：37.9±12.9%MVIC；MMG AMP：15.7±7.4%MVIC）大于 RPE 3（PF：30.0±14.5%MVIC；MMG AMP：10.2±6.5%MVIC），但 RPE 3 的 MMG 平均功率频率（MPF）（146.2±31.1%MVIC）大于 RPE 7（128.8±23.0%MVIC）。在 HTF 的 3 个可识别阶段中，RPE 依赖于力的降低（p≤0.01）。在这两个 RPE 中，MMG AMP 随时间减少，但 MMG MPF 或 SmO2 没有显著变化。在 RPE 之间，整体上有相似的运动单位控制策略和局部代谢需求。当 RPE 为 3 和 7 时，HTF 中大部分低于 CF 表明 CF 不能反映最高可持续力。当以 RPE 为锚定进行等长运动时，从业者应注意力的损失程度和任务的相对强度，以确保达到所需的训练负荷。
