Mannion A F, Dolan P
Comparative Orthopaedic Research Unit, University of Bristol, United Kingdom.
Spine (Phila Pa 1976). 1994 Jun 1;19(11):1223-9. doi: 10.1097/00007632-199405310-00006.
This was a cross-sectional study involving 229 healthy, back pain-free individuals.
To examine the relationship between electromyographic manifestations of fatigue and endurance time during isometric contraction of the back extensors to fatigue.
Despite the wide-spread use of electromyography to monitor muscle fatigue, its relationship with endurance time has not been well investigated.
Using skin-surface electrodes, electromyographic signals were recorded from thoracic (T10) and lumbar (L3) regions of erector spinae during an isometric endurance test, and the rate of change in median frequency of the electromyographic power spectrum (MFGRAD) was calculated.
MFGRAD was significantly higher at L3 than at T10. The best predictor of endurance time was given by the greater MFGRAD observed at either region. MFGRAD calculated over a submaximal time period (50% total time or 60 sec) also correlated significantly with endurance time. Women displayed a significantly longer endurance time and lower MFGRAD than men.
Endurance appears to be limited by the most fatigable region of the muscle group. MFGRAD is a suitable technique for monitoring back muscle fatigue, even when it is determined over a submaximal time period. The back extensors of women are less fatigable than those of men when the same task is performed.
这是一项横断面研究，涉及229名健康、无背痛的个体。
研究背部伸肌等长收缩至疲劳过程中疲劳的肌电图表现与耐力时间之间的关系。
尽管肌电图在监测肌肉疲劳方面应用广泛，但其与耐力时间的关系尚未得到充分研究。
在等长耐力测试期间，使用皮肤表面电极记录竖脊肌胸段（T10）和腰段（L3）的肌电信号，并计算肌电功率谱中位频率的变化率（MFGRAD）。
L3处的MFGRAD显著高于T10处。耐力时间的最佳预测指标是在任一区域观察到的更大的MFGRAD。在次最大时间段（总时间的50%或60秒）计算的MFGRAD也与耐力时间显著相关。女性的耐力时间明显长于男性，MFGRAD低于男性。
耐力似乎受肌肉群中最易疲劳区域的限制。MFGRAD是监测背部肌肉疲劳的合适技术，即使是在次最大时间段确定的情况下。在执行相同任务时，女性的背部伸肌比男性的更不易疲劳。
