Yamada Eiji, Kusaka Takashi, Arima Nobuo, Isobe Kenichi, Yamamoto Tetsuji, Itoh Susumu
Department of Rehabilitation, Faculty of Medicine, Kagawa University Hospital, Miki-cho, Kita-gun, Kagawa, Japan.
Clin Physiol Funct Imaging. 2008 Jul;28(4):216-21. doi: 10.1111/j.1475-097X.2008.00798.x. Epub 2008 Jul 1.
The purpose of this study was to clarify the relationship between electromyography (EMG) spectrum changes and muscle oxygenation measured by near-infrared time-resolved spectroscopy (TRS). Each subject performed sustained isometric knee extension at 50% of the maximal voluntary contraction load for 1 min. Surface EMG and TRS were simultaneously recorded from the right vastus lateralis muscle. Mean power frequency (MPF) of the power spectrum was calculated every 5 s during isometric contraction using fast Fourier transform, and decrease in the slope of MPF for 1 min was calculated using the least squares method. The maximal changes in oxygenated haemoglobin and myoglobin (Oxy Hb/Mb) and in deoxygenated haemoglobin and myoglobin (Deoxy Hb/Mb) from pre-contraction values of 1 min were calculated. There were significant relationships between the decrease in the slope of MPF and the maximal changes in Oxy Hb/Mb and Deoxy Hb/Mb (P < 0.05). These findings suggested that changes in Oxy Hb/Mb and Deoxy Hb/Mb indicate muscle fatigue assessed by EMG.
本研究的目的是阐明肌电图（EMG）频谱变化与通过近红外时间分辨光谱法（TRS）测量的肌肉氧合之间的关系。每位受试者在最大自主收缩负荷的50%下进行持续1分钟的等长膝关节伸展。同时从右侧股外侧肌记录表面肌电图和TRS。在等长收缩期间，每5秒使用快速傅里叶变换计算功率谱的平均功率频率（MPF），并使用最小二乘法计算1分钟内MPF斜率的下降。计算出与收缩前1分钟的值相比，氧合血红蛋白和肌红蛋白（Oxy Hb/Mb）以及脱氧血红蛋白和肌红蛋白（Deoxy Hb/Mb）的最大变化。MPF斜率的下降与Oxy Hb/Mb和Deoxy Hb/Mb的最大变化之间存在显著关系（P < 0.05）。这些发现表明，Oxy Hb/Mb和Deoxy Hb/Mb的变化表明通过肌电图评估的肌肉疲劳。
