Oberg T, Sandsjö L, Kadefors R
Department of Biomechanics, University College of Health Sciences, Jönköping, Sweden.
Ergonomics. 1994 Aug;37(8):1323-33. doi: 10.1080/00140139408964911.
In order to relate EMG signs of localized muscle fatigue to subjectively perceived muscle fatigue, a study was undertaken on 20 healthy volunteers exposing their right trapezius muscle by raising the arm to 90 degrees of abduction. Every person performed two contractions: 0 kg hand load during 5 min and 2 kg hand load during 2.5 min. Surface EMG was recorded and analysed with respect to RMS amplitude and mean power frequency (MPF). Subjective muscle fatigue was estimated with a psychophysical rating scale (Borg's CR-10 Scale). At high load level we found a significant correlation between MPF and the CR-scores (r = -0.46), but at low load level there was no correlation. At high load level there was a linear decrease of MPF with increasing load dose, but at low load level the MPF did not change, despite significant subjective fatigue. There was a linear rise of the CR-score with increasing load dose, more pronounced at high load level. It was concluded, that at low load levels common in working life, MPF and subjective scores seem to provide different fatigue information. Moreover, the MPF did not seem to work as a valid estimator of muscle fatigue at this low load level. Caution is recommended if it is to be used in static low-load situations.
为了将局部肌肉疲劳的肌电图（EMG）征象与主观感觉到的肌肉疲劳联系起来，对20名健康志愿者进行了一项研究，他们通过将手臂外展至90度来暴露右侧斜方肌。每个人进行两次收缩：5分钟内手部负荷为0千克，2.5分钟内手部负荷为2千克。记录表面肌电图，并就均方根（RMS）振幅和平均功率频率（MPF）进行分析。使用心理物理学评分量表（博格CR-10量表）评估主观肌肉疲劳。在高负荷水平下，我们发现MPF与CR评分之间存在显著相关性（r = -0.46），但在低负荷水平下则无相关性。在高负荷水平下，MPF随着负荷剂量的增加呈线性下降，但在低负荷水平下，尽管主观疲劳明显，MPF却没有变化。CR评分随着负荷剂量的增加呈线性上升，在高负荷水平下更为明显。得出的结论是，在工作生活中常见的低负荷水平下，MPF和主观评分似乎提供了不同的疲劳信息。此外，在这种低负荷水平下，MPF似乎不能作为肌肉疲劳的有效估计指标。如果要在静态低负荷情况下使用，建议谨慎。
