MUSCULAR WORKING ANALYSIS OF SPIKING ACTION ON THE VOLLEYBALL
AbstractPREFACE We studied two different muscular positions in the spiking action, they are back swing and high lifting on the straight smash. It provides reference for coaches about teaching and training. Youth and juvenile are especially taught and trained by coaches. METHOD Ten volleyball players (men) were selected as subjects in this study. Players smash at the left forward and the setter of skilled movement passed a ball to the center forward. The experimental instrument was 200 electromyogram instrument (made in Denmark). Sticking of skin surface electronic board is adopted by us. Abdominal rectus muscle, erector spinal muscle, trapezius muscle, anterior serrtus muscle, greater pectoral muscle, deltoid muscle, bicepts muscle of upper arm, round pronator muscle, radial flexor muscl. dialis brevis muscle and larger round muscle, tricep muscle upper arm. RESULT Back swing phase of high lifting spiking player's upper limb from flexion to abduction and their upper limb lifts from outer up to the best of the player ability. The elbow joint was higher than the shoulder joint. Muscular discharge form were seen this moment. Order of muscular contraction were bicepts muscle of upper arm, the front of deltoid muscle and clavicle part of greater pectoral muscle. From the point of view of the time course of the muscle contraction, bicepts muscle of upper arm is the longest. Contracting time of other muscles decrease progressively step by step. Muscular discharge of shoulder and elbow joint disappear from back swing to front swing. It showed that these muscles had entirely relaxed. When the upper limb lifted to begin the front swing, discharge of radial flexor muscle, round pronator muscle and tricep muscle showed the main joint began to flex, elbow joint extension and internal rotation. At this the front part of deltoid muscle and clavicle part of greater pectoral showed that shoulder joint has internal rotational movement. The front part of deltoid muscle not only can flex for shoulder joint, but also can be internal rotation. When players are swinging the arm to the back the back swing is different from high lifting on shoulder joint's muscles discharge form. The clavicle part of greater pectoral muscle has not discharged, deltoid muscle and large round muscle discharge. These muscles' discharge showed shoulder joint extension under shoulder joint. When players are in a period of transition from back swing to front swing. Muscular discharge from the shoulder and elbow joint are different from the front swing to touching volleyball, the front, middle and back of deltoid muscle are different each time on the discharge. The middle and back part of the deltoid muscle contracts longer, the front part of deltoid muscle contracts shorter. After spiking, shoulder joint's discharge muscular majority are different from high lifting. It showed that these muscles contract unnecessarily. CONCLUSION I. When players are in a period of transition from back swing to front swing, muscular discharge of shoulder and elbow joints were very weak between back swing and high lifting. 2. Later stages of the swing of arm to the front, muscular discharge form of the front middle and back of deltoid muscle are similar for high lifting, their applied force was concentrated, but three sections of the muscles of deltoid muscle were different, their applied force scattered.