Rua Riccardo, Bondi Danilo, Santangelo Carmen, Pignatelli Pamela, Pietrangelo Tiziana, Fulle Stefania, Fanelli Vito, Verratti Vittore
Department of Surgical Science, Anaesthesia and Critical Care, University of Turin, Torino.
Department of Neuroscience, Imaging and Clinical Sciences, University "G. d'Annunzio" of Chieti - Pescara, Chieti.
Eur J Transl Myol. 2023 Sep 12;33(3):11637. doi: 10.4081/ejtm.2023.11637.
Reports of electromyography during hypoxic exercise are contrasting, due to protocol and muscle diversity. This work aimed to investigate alterations in muscle activation and myoelectrical fatigue during exercise at high-altitude in those muscles primarily involved in trekking. Twelve young adults balanced by gender and age were tested at low (1,667 m) and high (4,554 m, "Capanna Margherita", Italy) altitude, during an isometric squat lasting 60 seconds. High-density surface electromyography was performed from the quadriceps of right limb. The root mean square (RMS), median frequency with its slope, and muscle fiber conduction velocity (MFCV) were computed. Neither males nor females showed changes in median frequency (Med: 36.13 vs 35.63 Hz) and its slope (Med: -9 vs -12 degree) in response to high-altitude trekking, despite a great inter-individual heterogeneity, nor differences were found for MFCV. RMS was not significantly equivalent, with greater values at low altitude (0.385 ± 0.104 mV) than high altitude (0.346 ± 0.090 mV). Unexpected results can be due either to a postural compensation of the whole body compensating for a relatively greater effort or to the inability to support muscle activation after repeated physical efforts. Interesting results may emerge by measuring simultaneously electromyography, muscle oxygenation and kinematics comparing trekking at normoxia vs hypoxia.
由于实验方案和肌肉多样性的原因，关于低氧运动期间肌电图的报告相互矛盾。这项研究旨在调查在高海拔地区徒步旅行时，主要参与运动的肌肉的肌肉激活和肌电疲劳的变化。选取了12名年龄和性别均衡的年轻人，在低海拔（1667米）和高海拔（4554米，意大利“玛格丽塔小屋”）进行测试，进行一次持续60秒的等长深蹲。对右下肢股四头肌进行高密度表面肌电图检查。计算均方根（RMS）、中位数频率及其斜率，以及肌纤维传导速度（MFCV）。尽管个体间存在很大差异，但无论是男性还是女性，在高海拔徒步旅行后，中位数频率（中位数：36.13对35.63赫兹）及其斜率（中位数：-9对-12度）均未显示变化，MFCV也未发现差异。RMS并不显著相等，低海拔时的值（0.385±0.104毫伏）高于高海拔时的值（0.346±0.090毫伏）。意外的结果可能是由于全身的姿势补偿以弥补相对更大的努力，或者是由于反复体力活动后无法维持肌肉激活。通过同时测量肌电图、肌肉氧合和运动学，比较常氧与低氧条件下的徒步旅行，可能会得出有趣的结果。
