Abstract
[Purpose] In a preparatory study investigating the utility of mechanomyograms for muscle activity evaluation, we examined and compared the relationship between voluntary contraction of the deltoid muscle and muscle activity with electromyograms (EMGs) and mechanomyograms (MMGs). [Subjects] The subjects were 8 normally healthy persons (average age 21.4 ± 0.5 years). [Method] Maximal voluntary isometric contraction (MVC) with the right shoulder joint at 90 degrees abduction was calculated, and the integrated EMG (IEMG) and integrated MMG (IMMG) at 10%, 20% and 30% of MVC was determined, and compared with each MVC value. [Results] Significant increases (p<0.01) between each MVC load value were found for both IEMG and IMMG. In addition, IMMG showed an almost equal increase for each load step, whereas equal increases in relation to load were not seen for IEMG. [Conclusion] MMG reflected increases in muscle force better than EMG, suggesting the possibility of its usefulness as a parameter of muscle activity.
