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目的:通过观察肘关节屈伸运动过程中主动肌和拮抗肌表面肌电图(sEMG)信号活动,探讨不同强度运动诱发肌肉疲劳的中枢运动控制规律。方法:11名男性受试者完成3组不同负荷的肘关节屈伸运动实验,采用线性(AEMG、MPF)和非线性(C(n)、%DET)分析方法,对不同强度下屈伸肘运动中主动肌(肱二头肌,BB)和拮抗肌(肱三头肌,TB)的sEMG信号及共激活比值(CR)进行研究。结果:向心屈肘关节运动条件下,主动肌BB的AEMG呈现5kg和15kg不变而10kg负荷随收缩次数的递增逐渐增加的现象,拮抗肌TB的AEMG在所有运动强度条件下均未表现出明显增加的现象;向心屈肘关节运动过程中,AEMG和MPF斜率受运动负荷强度和主动肌/拮抗肌因素双重影响,C(n)和%DET斜率仅存在运动强度效应,不存在主动肌/拮抗肌效应;向心屈肘关节运动过程中主动肌和拮抗肌的CRAEMG、CRMPF、CRC(n)和CR%DET均具有明显的运动强度效应而无收缩次数效应,且向心屈肘和离心伸肘运动有相似的变化规律。结论:共激活现象在线性指标和非线性指标上呈现不同变化;共激活作用的变化受运动强度的影响,不受肌肉疲劳因素的影响;不同强度肘关节屈伸运动过程中,中枢神经系统对主动肌和拮抗肌运动单位的募集可能采取了不同的控制策略。
OBJECTIVE: To investigate the central motor control rules of muscular fatigue induced by exercise with different intensities by observing the sEMG signal activities of the active and antagonistic muscles during flexion and extension of the elbow joint. Methods: Eleven male subjects completed the flexion and extension exercise of elbow joint under different loads. The flexion and extension elbow flexion and extension were performed under different intensities by using linear (AEMG, MPF) and nonlinear (C (n),% DET) The sEMG signal and coactivation ratio (CR) of active muscle (biceps, BB) and antagonist muscle (triceps, TB) were studied. Results: In the case of flexion-elbow joint movement, the AEMG of aortic muscle showed a gradual increase of 5kg and 15kg while the load of 10kg increased gradually with the number of contractions. AEMG of antagonistic muscle did not show any effect on exercise intensity (P <0.05). The slope of AEMG and MPF were both influenced by exercise load intensity and active muscle / antagonist muscle factors. The slope of C (n) and% DET only existed the effect of exercise intensity, and there was no active muscle / Antagonistic muscle effect. CRAEMG, CRMPF, CRC (n) and CR% DET of active and antagonistic muscles during flexion-to-elbow flexion exercise all had significant exercise intensity effect without contracting number of times, Centrifugal extension elbow movement similar to the law of change. CONCLUSION: Co-activation phenomena show different changes in linear and non-linear indexes. The changes of co-activation are affected by exercise intensity, but not by muscle fatigue factors. During the flexion-extension exercise of different strength elbow joints, Muscle and antagonist muscle recruitment units may take different control strategies.