Electromyographical study of the pectoralis major (sternocostal part) and deltoid muscles (middle fibers) in volleyball sequential actions.

UNLABELLED

The Pectoralis Major muscles (Sternocostal part) and Deltoid (middle fibers) had been studied using electromyography in 8 male individuals, who practice volleyball, youth category, (age between 15 and 17 average +/- 16,25 years old), right-handed, those involved in volleyball for about one year. The objective was to analyze the potential of action of these muscles engaged in the volleyball movements: service, spike, pass, set and blocking with and without ball. The work was developed in the Electromyography and Biomechanics of Posture Laboratory(Physical Education Faculty--State University of Campinas--UNICAMP). To caption the muscle action potential, surface electrodes were set with conductive gel and fixed on the skin, in the center of the muscles. It was used an electromyography Lynx with 6 channels. The apparatus calibration was 2.500 microV, 1199.760 Hz. The low and high pass filter was set at 600-10 Hz. The sequential experiments without ball were performed for 10 seconds, and the sequential experiments with ball in 12 seconds.

RESULTS

The Pectoralis Major muscle (Sternocostal part) revealed active during the basic movements of volleyball, (service and spike) in all movements of the extension of the arm, as well as the arm abduction during the pass movement. The Deltoid muscle (middle fibers), in spite of being primary in the abduction, showed the potential of action in all movements practiced in volleyball, however, they were more intense, in the spike and block actions. It is interesting to observe, that the general average and the standard deviation of the Deltoid muscle (middle fibers), were higher in the sequential movements executed without ball.