Sustained Muscle EMG Activity to Contractile Failure During Incremental Exercise and Intense Constant Load Cycling: No Evidence of a Central Governor

Qeios Pub Date : 2024-05-14 DOI:10.32388/f7ew12
Alexander R Holmans, R. Robergs, Bridgette O'Malley
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Abstract

Since 1997, debate has continued over the presence of a central governor that constrains neuromuscular activity during severe, intense exercise. This study aimed to challenge the central governor model (CGM) through acquiring surface electromyography (sEMG) data from the vastus lateralis (VL) and gluteus maximus (Gmax) muscles of 14 healthy participants during 4 different bouts of constant load, non-steady state cycling exercise (110, 125, 140, 160 %watts at the ventilation threshold), and 1 incremental bout to volitional exhaustion. sEMG activity was processed to isolate and capture each contraction of the VL and Gmax during all bouts of exercise. sEMG data was then graphed to profile sEMG root mean square (rms) activity over time with linear curve fitting used to quantify this relationship for data preceding (segment 1) and during the final 30s of each test (segment 2). Two-way repeated measures ANOVA was used to test for differences between the slopes of the two linear segments of the sEMG rms response of the VL for each bout. Results during the VO2max trial revealed a significant main effect for SEGMENT where segment 2 was significantly greater than segment 1 (F=6.741, p=0.023). During the critical power trails there were significant differences in sEMG rms for each of INTENSITY (F=9.349, p<0.001), SEGMENT (F=5.443, p=0.036), and the interaction effect (F=2.837, p=0.005). Muscle sEMG rms data revealed sustained increases in muscle activity in all bouts of intense exercise to volitional exhaustion in both the VL and Gmax, which is inconsistent with the predictions made from the CGM.
在增量运动和高强度恒定负荷自行车运动中,肌肉肌电图活动持续到收缩衰竭:没有证据表明存在中央调速器
自 1997 年以来,人们一直在争论在剧烈的高强度运动中,是否存在一个制约神经肌肉活动的中枢调控器。本研究旨在通过获取 14 名健康参与者在 4 次不同的恒定负荷、非稳态骑车运动(通气阈值为 110、125、140、160% 瓦特)和 1 次达到意志衰竭的递增运动中的外侧阔肌(VL)和臀大肌(Gmax)的表面肌电图(sEMG)数据,对中央调速器模型(CGM)提出质疑。对 sEMG 活动进行处理,以分离和捕捉所有运动过程中 VL 和 Gmax 的每次收缩。然后将 sEMG 数据绘制成曲线图,以描绘 sEMG 活动随时间变化的均方根(rms),并使用线性曲线拟合来量化每次测试之前(第 1 段)和最后 30 秒期间(第 2 段)的数据关系。使用双向重复测量方差分析来检验每次测试中 VL 的 sEMG 均方根响应的两个线性段斜率之间的差异。VO2max 试验的结果显示,SEGMENT 的主效应显著,其中第 2 段显著大于第 1 段(F=6.741,p=0.023)。在临界功率试验中,强度(F=9.349,p<0.001)、SEGMENT(F=5.443,p=0.036)和交互效应(F=2.837,p=0.005)对 sEMG rms 均有显著差异。肌肉 sEMG rms 数据显示,在 VL 和 Gmax 的所有剧烈运动到意志衰竭的过程中,肌肉活动都持续增加,这与 CGM 的预测不一致。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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