摘要
目的:分析表面肌电(sEMG)信号指标评定低负荷等长收缩诱发运动性肌肉疲劳的敏感性和稳定性,为疲劳评价提供参考。方法:以15名男性青年志愿者为研究对象,先测试受试者屈肘关节最大自主收缩力矩(Maximal Voluntary Contration,MVC),令受试者右臂腕部拉住可在肘关节处产生20%MVC的重物,记录右侧肱桡肌和肱二头肌sEMG,至不能坚持负荷时结束实验。计算时域指标均方根振幅(RMS),基于傅里叶变换计算中值频率(MF)和平均功率频率(MPF),基于小波包分析计算中值频率(MDF)和平均功率频率(MNF),基于非线性分析计算Lempel-Ziv复杂度C(n)。评定上述指标在低负荷等长收缩诱发屈肘肌疲劳方面的敏感性和稳定性。结果:肱二头肌与肱桡肌sEMG的RMS随负荷实验持续时间延长表现出逐渐增加的趋势,而MF、MPF、MDF、MNF、C(n)则表现出逐渐减小的趋势。MF、MPF、MDF、MNF、C(n)与负荷运动持续时间之间具有显著负相关,RMS与负荷运动持续时间之间具有显著的正相关。肱二头肌与肱桡肌RMS反映疲劳的敏感性和稳定性优于其他指标。结论:由于低负荷收缩诱发疲劳引起募集运动单位数量增加等因素作用,RMS表现出较显著的增加趋势,是评定由低负荷等长收缩诱发屈肘肌疲劳的较好指标。
Objective The sensitivity and stability of sEMG during muscle fatigue induced by isometric contraction was evaluated. Methods Fifteen young man participated in this experiment. The isomeric contraction of elbow flexion was performed with the load of 20% individual maximal voluntary contraction. At the same time, sEMG signals were collected from biceps brachi （BB） and brachioradialis （BR）, then root mean square （RMS）,Fourier transformation-based medium frequency （MF） and mean power frequency （MPF）, wavelet packet transformation-based medium freauencv （MDF） and mean power frequency （MNF）, and nonlinear Lempel-Ziv complexity （Cn） were calculated and their sensitivity andstability were compared. Results The results showed that MF,MPF,MDF,MNF,and （Cn） of BB and BR decreased when muscle fatigue appeared with significant negative correlation to contraction duration, especially RMS revealed the highest sensitivity and stability to the muscle fatigue. Conclusion RMS is the better parameter for evaluating muscle fatigue caused by low-intensity isometric contractions.
出处
《中国运动医学杂志》
CAS
CSCD
北大核心
2013年第2期117-123,163,共8页
Chinese Journal of Sports Medicine
基金
上海体育学院研究生教育创新基金(YJSCX201107)
上海市人类运动能力开发与保障重点实验室(上海体育学院)(项目编号:11DZ2261100)
关键词
表面肌电信号
疲劳
低负荷等长收缩
适用性
sensitivity, surface electromyography, muscle fatigue,isometric contraction
