2005 Volume 3 Issue Special_Issue_2005 Pages 280-285
To examine the origin of mechanomyogram (MMG), we compared the responses of surface MMG with the changes in the fascicle length determined by ultrasonography during electrically induced contractions of human skeletal muscles. The posterior tibial nerve of subjects (n=5) was stimulated with a stimulus pattern in which the frequency rose up from 1Hz to 20Hz linearly. The MMG amplitude decreased with increasing stimulation frequency. Reduction of MMG amplitude was in parallel with the decrease in fluctuation of the changes in fascicle length, and these values had a significant positive correlation (r=0.94, P<0.001). The observed direct relation between MMG and architectural change of muscle indicates that surface MMG is generated by the pressure wave produced by the expansion of a number of muscle fibers during contractions.