| Spiking techniques,being one of the most important ways of scoring,have been playing a dominant role in volleyball games.Well-performed spiking could not only encourage the teams,but also determine the results of the games.Ball-hitting is the essential moment and factor of spiking technique.Therefore,it is a necessity to conduct some studies about it.By means of documents,interviews,tests and statistics,the paper takes a survey of 6 attackers in sports universities on their ball-hitting techniques.Throughout the research,high-speed cameras and EMG tests are used to capture the specific details of the muscles in different time and space dimensions in order to find out the basic regularities and characteristics of ball-hitting techniques,which could be helpful in understanding muscle strength and specific EMG features of spiking techniques,as well as providing theoretical reference for volleyball teaching or training.The research draws some conclusions:Firstly,the flexion range of the right knee joint is wider than the left during ball-hitting period,whereas,the flexion range of the hip joints shows almost no difference in pre-swing period.The right hip joint increases flexion range in the arm swing period.Secondly,the angle displacements of right shoulder joint and right elbow joint are positive related to the palm-fingers’ center speed in the ball-hitting period.Meanwhile,the right shoulder joint in ball-hitting period of the testers are not fully extended.The extension of right elbow joint has not reached the theoretical value.Thirdly,swing and ball-hitting period lasts shorter than pre-swing period,and palm-fingers center speed is determined by the total time duration of pre-swing.Therefore,the faster of palm-fingers speed,the faster of arm swing ball-hitting.The fourth point shows that the height of body gravity is positively related to the palm-fingers center speed.The same patterns are also applied to the speed of body weight and palm-fingers center speed during fully-extended pre-swing period and ball-hitting period.The fifth point shows that in arm’s pre-swing period,the muscles of frontal deltoids,biceps,spine erectors and trapezius have a better contribution rate,Whereas,the muscles of extensor radialis carpus,external obliques,triceps and flexor radialis carpus contribute less.In the arm’s swing period,the pattern differs a little bit,that is deltoids and triceps contribute more than those ofpectorals,external oblique,trapezius,erector spine muscle and radiocarpus.Finally,the statistics display that in the ball-hitting period the muscles of frontal deltoids have the most electric intensity,and the muscles of external obliques and flexor radialiscarpus have the lest electric intensity.Based on the conclusions above,the research has promoted some suggestions:First,it is strongly recommended that players should enhance lower limbs integration and coordination exercises and develop the power delivery effects by extending knee joints simultaneously.Meanwhile the height of ball-hitting could be improved by bounce training,while ball-hitting performance could be more reasonable and well-performed with angle extension of shoulder and elbow.Secondly,the players should enhance their speed abilities of ball-hitting,therefore,the better performance could be obtained by declining the total time duration of arm swing and ball-hitting.Thirdly,advanced fitness training should be applied in order to improve muscle power and engagement by focusing on the muscle training of frontal deltoids,biceps,posterior deltoids and rectus abdominis,which have more contribution rate in ball-hitting.Fourthly,research methods of volleyball training should be enriched,for example,by applying kinematics.Meanwhile,contractive research among groups with various level,height and weight features should be conducted to analyze these factors’ influence on the attacking abilities with EMG specific factors. |
