| Purpose:In order to make volleyball coaches and athelets know more in-depth technical structures of volleyball spiking action and the characteristics of muscle activity when spiking, and to let the training on the volleyball athletes more targeted in the later physical stamina training and technical training.Subjects:8 male volleyball athletes at BSU volleyball team (Height:1.95±0.04m; weight:88±11kg; Age:22±1 years old).Experimental Action:the spike action in the front-row fourth position and the back row sixth position.MethodsKinematics Methods:Use two three-dimensional high-speed cameras for filming, with a frequency of 200Hz. And the two machines were fixed in two places, one is the front of right flank of the subjects'heading, and the other is the back of right flank. The intersection angle of main axis of the two machines is about 100°. In addition, we must be sure of the demarcation of three-dimensional framework and the landmark calibration before shooting.Kinetics Methods:Four 40×60cm Kistler three-dimensional force platforms were combined into a 80×120cm force platform. Every qualified action of subjects in the experiment must let both feet stand on the 80×120cm force platform.EMG Methods:Do EMG acquisitions on 29 muscles of the human body using ME6000-type surface EMG acquisition system (16 channels) produced in Finland, The EMG is divided into two programs to be tested in order. Do comprehensive testing with the three methods, including that force platforms and surface electromyography test must synchronize, and the synchronous signal is triggered by surface electromyography. In the same time control the high-speed_camera'shooting manually so as to be sure that the tests of kinematics, kinetics and surface electromyography synchronize as possible.Data analysisIt is found that the eight subjects were divided into two types of technology in the data processing:With-Arm-Swing-Type (A-type) and Without-Arm-Swing-Type (B-type). So the data analysis should not only include comparative analysis of the same type of foward and backward spike, but also different types of foward and backward spike.Conclusionl.The A-type of foward and backward spiking has very significant differences in the technical characteristics. In the take-off stage, the range of motion of forward spiking is larger than the backward spiking. But on the contrary, in air ball stage, the range of motion of backward spiking is larger than the foward spiking; However, the foward and backward spiking action of the B-type technology are fairly consistent with each other, but the range of motion of backward spiking is greater than the foward. To compare A-type with B, the B-type has features of larger range of motion and longer time.2. The A-type has a short buffer time, facing large reaction force; in the contrast, the B-type has a long buffer time, facing small reaction force.3. The A-type has a balanced muscles activity and a considerable contribution of each muscle, but the primary and secondary muscles are not obvious. The B-type has a more obvious relationship between primary and secondary muscles, and the size of discharge of each muscle has striking differences. Moreover, the muscle activities are not banlanced. Let A compare with B:B-type contains a greater amount of muscle discharge and more muscles acting.
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