An electromyographic effect from biceps brachii muscles during isometric contraction varying the range of motion (ROM) of the elbow

Abstract

It is well recognized that, electromyography (EMG) signals are manipulated by the exact electrode placement in the active muscle. In this paper, we presented the effect of muscle strength in three locations of the biceps brachii muscles (bicep belly, lower part of the belly and upper portion of the belly) during isometric contraction. Two types of range of motion (ROM) for elbow was selected, 110° and 90°. Four healthy male subjects (n=4, mean age=24.4 years, 68kg, 164cm, BMI=21.2) were volunteered in this experiment. A wireless EMG sensor, digital dynamometer and angle meter were used for the measurement. Average EMG (EMGAVG), root mean square (EMGRMS), standard deviation (SD), highest EMG peak and standard error (SE) were analyzed. Then, all the dependant variables were calculated using repeated measures analysis of variation (ANOVA). From the experiment, result of EMGRMS and a highest peak value shows that there was an interaction in bicep muscles (three locations) between 110° and 90° elbow angle (p=0.047, i.e.<0.05), but there was no effect between these two angles with the result of SD,SE and EMGAVG. The finding results are important to compare with other muscles of upper arm, bicep rehabilitation and other physical therapy.