不同振动条件下的正常人体下肢肌肉表面肌电分析

关键词：振动刺激  表面肌电  均方根振幅  频率  谐振

Keywords:vibration stimulation  surface electromyogram  root mean square  frequency  resonance

摘要：

      摘要 目的：通过施加不同条件下的局部振动刺激，探讨局部振动刺激对于正常人体下肢主要肌肉群的影响。利用表面肌电（sEMG）分析的方法探寻局部振动刺激最佳的振动频率与位置。 方法：正常男大学生10名，年龄（23.0±1.7）岁，身高（173.5±4.5）cm，体重（70.4±8.2）kg。分别于屈膝30°半蹲位接受频率为10—50Hz的振动刺激，并采集振动前，振动中的表面肌电。选取左腿股直肌（REC）、半腱肌（SEM）、左腿胫骨前肌（TA）与腓肠肌内侧头（MG）作为试验检测肌肉，分别以左胫骨前肌远端和跟腱为振动刺激点。分析不同条件的振动刺激激活下肢肌群的表面肌电特征。 结果：各种振动条件刺激均引起小腿肌肉放电量增加（P＜0.05)。胫骨前肌的肌电值在两种刺激位置下且在不同频率间差异均有显著性意义（P＜0.05），但30Hz、40Hz、50Hz间差异无显著性意义。腓肠肌的肌电值在胫前肌刺激位置下各频率间差异无显著性意义，跟腱刺激点下各种频率间均存在显著性差异（P＜0.05），但30Hz、40Hz、50Hz间差异无显著性意义。各种振动条件刺激对大腿肌肉肌电值影响均无显著性意义。 结论：不同条件的小腿局部振动刺激均引起小腿肌肉放电量增加，未对大腿肌肉产生显著影响。频率30—50Hz为正常人体小腿肌肉最佳的振动刺激频率。振动刺激作用在肌腱位置能有效引起肌肉兴奋，跟腱较胫前肌肌腱位置更易激活小腿肌肉肌群。

Abstract:

      Abstract Objective: To explore the influence of vibration stimulation on normal humans lower limbs major muscles under different local vibration stimulation conditions, and to determine the best vibration frequency and location by surface electromyogram(sEMG) analysis. Method: Ten normal male college students [age (23.0±1.7)years, height (173.5±4.5)cm, weight (70.4±8.2)kg] were involved in this study. All of them were in squat (knee flexion 30°) position, accepted the vibration stimulations with 10—50Hz frequencies and sEMG were collected. Left rectus femoris and semitendinosus, left anterior tibial muscle and the medial head of gastrocnemius were selected for detection, the vibration stimulation point was on the surface of distal of left anterior tibial muscle and achilles tendon, respectively. The sEMG characteristics under different vibration stimulations on lower limbs major muscles were analyzed. Result: The calf muscles were activated significantly under different vibration conditions (P＜0.05). The sEMG values of anterior tibial muscle were significantly different with vibration frequency increasing (P＜0.05). However, there was no significant difference among 30Hz, 40Hz and 50Hz on the two positions (P＞0.05). The gastrocnemius EMG values were not significantly different with vibration frequency increasing(P＞0.05), as the vibration location was on the distal of left anterior tibial muscle. But on the achilles tendon the sEMG values of gastrocnemius were significantly different with vibration frequency increasing(P＜0.05), and there was no significant difference among 30Hz, 40Hz and 50Hz(P＞0.05). The thigh muscles were not activated significantly under different vibration conditions(P＞0.05). Conclusion: The calf muscles were activated significantly under different vibration conditions, but the thigh muscles were not activated significantly. The vibration frequency at 30—50Hz might be the best activated frequency for calf muscles. The vibration stimulation on tendon position could effectively cause muscle excited，and achilles tendon was more likely to activate the calf muscles than the anterior tibial muscle.