Department of Kinesiology and Integrative Physiology, Michigan Technological University, 1400 Townsend Dr, Houghton, MI 49931, USA.
Department of Physical Education, Kangwon National University, 1 Gangwondaehak-gil, Hyoja-dong, Chuncheon-si, Gangwon-do 24341, Korea.
Int J Environ Res Public Health. 2020 Oct 1;17(19):7194. doi: 10.3390/ijerph17197194.
The purpose of this study was to examine prefrontal cortex (PFC) activation, neuromuscular function, and perceptual measures in response to a fatiguing task, following thermal alterations of an exercising arm. Nineteen healthy adults completed three experimental sessions. At baseline, participants performed maximum voluntary isometric contractions (MVIC) of the elbow flexors. Next, participants submerged their right arm in a water bath for 15 min. Cold (C), neutral (N), and hot (H) water temperatures were maintained at 8, 33, and 44 °C, respectively. Following water immersion, participants performed an isometric elbow flexion contraction, at 20% of their MVIC, for 5 min. Ratings of perceived exertion (RPE), muscular discomfort, and task demands were assessed. Functional near-infrared spectroscopy was used to measure activation (oxygenation) of the PFC during the fatiguing task. Reductions in MVIC torque at the end of the fatiguing task were greater for the H (25.7 ± 8.4%) and N (22.2 ± 9.6%) conditions, compared to the C condition (17.5 ± 8.9%, < 0.05). The increase in oxygenation of the PFC was greater for the H (13.3 ± 4.9 μmol/L) and N (12.4 ± 4.4 μmol/L) conditions, compared to the C condition (10.3 ± 3.8 μmol/L, < 0.001) at the end of the fatiguing task. The increase in RPE, muscular discomfort, and task demands were greater in the H condition compared to the N and C conditions ( < 0.01). These results indicate that precooling an exercising arm attenuates the rise in PFC activation, muscle fatigue, and psychological rating during a fatiguing task.
本研究旨在探讨热改变运动手臂后，前额皮质（PFC）的激活、神经肌肉功能和感知测量在疲劳任务中的反应。19 名健康成年人完成了三个实验阶段。在基线时，参与者进行了最大自主等长收缩（MVIC）的肘部屈肌。接下来，参与者将右臂浸入水浴中 15 分钟。冷水（C）、中性（N）和热水（H）的温度分别保持在 8、33 和 44°C。水浸后，参与者以 20%的 MVIC 进行 5 分钟的等长肘部屈曲收缩。评估了感知用力（RPE）、肌肉不适和任务需求。功能近红外光谱用于测量疲劳任务中 PFC 的激活（氧合）。与 C 条件（17.5 ± 8.9%，<0.05）相比，H（25.7 ± 8.4%）和 N（22.2 ± 9.6%）条件下疲劳任务结束时 MVIC 扭矩的降低更大。与 C 条件（10.3 ± 3.8 μmol/L，<0.001）相比，H（13.3 ± 4.9 μmol/L）和 N（12.4 ± 4.4 μmol/L）条件下疲劳任务结束时 PFC 氧合的增加更大。与 N 和 C 条件相比，H 条件下 RPE、肌肉不适和任务需求的增加更大（<0.01）。这些结果表明，预冷却运动手臂可减轻疲劳任务中 PFC 激活、肌肉疲劳和心理评定的升高。
