Krause K H, Magyarosy I, Gall H, Ernst E, Pongratz D, Schoeps P
Friedrich-Baur-Institute, University of Munich, Germany.
Electromyogr Clin Neurophysiol. 2001 Mar;41(2):67-70.
The purpose of this study was to investigate the effects of cooling and heating of muscles on parameters of surface EMG (SEMG) under various well defined grades of isometric muscle contraction. In 32 healthy volunteers, aged 20-30 years, turns and amplitude (RMS) analysis was done in SEMG from the hand extensors. Muscle strength was defined by a new developed hand dynamometer. Values for RMS and turns in case of maximal voluntary contraction (MVC) over periods of 20 sec were determined for each volunteer and subsequently RMS and turns were measured during isometric contractions of 10%, 30%, 50% and 80% of MVC, interrupted each by rest periods. This procedure was repeated after cooling and warming the forearm with thermo packs. For control purposes the same investigations with three measurement periods of SEMG were done following the same time schedule without thermic stimuli. With increasing isometric contractions turns increased after heat application and decreased after ice application, compared to the values achieved without thermic stimuli. The differences were significant from a level of 30% of MVC (p < 0.05). No corresponding changes were seen for RMS. In the control experiment values of turns and RMS did not differ in the three measurement periods. It is concluded, that the amplitude in SEMG tracings seems to be a reliable parameter of muscle force, whereas turns are sensitive to temperature. They might be useful markers for therapeutic approaches targeted at the muscle.
本研究的目的是在各种明确界定的等长肌肉收缩等级下，研究肌肉冷却和加热对表面肌电图（SEMG）参数的影响。在32名年龄在20至30岁的健康志愿者中，对来自手部伸肌的SEMG进行了转折和振幅（均方根，RMS）分析。肌肉力量由一种新开发的握力计定义。确定了每位志愿者在20秒的最大自主收缩（MVC）期间的RMS和转折值，随后在MVC的10%、30%、50%和80%的等长收缩期间测量RMS和转折，每次收缩之间有休息期。在前臂用热敷袋冷却和加热后重复此过程。为了进行对照，按照相同的时间安排在没有热刺激的情况下对SEMG进行三个测量期的相同研究。与没有热刺激时获得的值相比，随着等长收缩增加，热应用后转折增加，冰应用后转折减少。差异从MVC的30%水平开始显著（p<0.05）。RMS没有相应变化。在对照实验中，转折和RMS的值在三个测量期没有差异。得出的结论是，SEMG描记图中的振幅似乎是肌肉力量的可靠参数，而转折对温度敏感。它们可能是针对肌肉的治疗方法的有用标志物。
