The purpose of the present investigation was to determine changes of the electrically evoked mechanomyogram (MMG) with different stimulation intensities.The electrical stimulation was applied to the motor point of the palmaris longus muscle to produce single twitch contraction,and the MMG was recorded from the muscle berry with a small accelerometer.The peak amplitude of the MMG in the first positive phase increased with increasing stimulation intensity,however,the increment of the peak MMG amplitude (the derivative of the increasing amplitude) progressively reduced.The results suggest that the relationship between the MMG amplitude and stimulation intensity during single twitch contraction reflects the recruitment of different ty es of the motor units.
Aichi Human Service Center,Kasugai,Japan Bio-mimetic Control Research Center,the Institute of Physic Bio-mimetic Control Research Center,the Institute of Physical and Chemical Research(RIKEN),Nagoya,Ja Bio-mimetic Control Research Center,the Institute of Physical and Chemical Research(RIKEN),Nagoya,Ja Bio-mimetic Control Research Center,the Institute of Physical and Chemical Research(RIKEN),Nagoya,Ja Bio-mimetic Control Research Center,the Institute of Physical and Chemical Research(RIKEN),Nagoya,Ja Osaka Electro-Communication University,Shijonawate,Japan Bio-mimetic Control Research Center,the Institute of Physical and Chemical Research(RIKEN),Nagoya,Ja