Recruitment and Decruitment of Motor Units Activities of M. Biceps Brachii during Isovelocity Movements

The purpose of this study is to investigate behaviors of motor units of m. biceps brachii (biceps short head muscle) during flexion movements in wide range of elbow joint angle. In this study, eight surface electromyograms(EMGs) were measured during flexion movements at constant angular velocity (isovelocity) and against constant torque in wide range (from 0 [deg] to 120 [deg]) of elbow joint angle with a surface electrode array. We identified action potensials of each moitor unit and detected recruitment and decruitment of the identified motor units. We found 42 recruitments and 38 decruitments of the motor units in 42 experimental sessions, 6 subjects. Keywords— motor unit, electromyogram, biceps brachii, recruitment, decruitment