| Research Purposes: according to the research,the backhand stroke score rate has become the most important factor besides the service score rate and the receive score rate in the tennis match,and is gradually becoming an important factor affecting the implementation of techniques and tactics.In order to reveal the difference of backhand double-hand top spin in baseline tennis,and further understand the important factors affecting the backhand double-hand top spin in baseline tennis.To observe and analyze the differences between the professional athletes and the specialized students in the technique of backhand double-hand hitting topspin,so as to prompt the specialized students or the tennis lovers to realize the irrationality of their skills and the advantages of the athletes,more conducive to specific students or tennis lovers learn from each other,targeted training and learning,but also for the teacher’s teaching or tennis director of sports to provide some reference.Research Methods: through the establishment of human kinematics model,this paper realizes the quantitative analysis of Human Joint Angle,joint velocity and so on,which can accurately analyze the rotating and linear motion of the components in human body mechanism.It is of great significance to study the position of human body in space motion,the best exertion and the best stress of human body.The study selected 10 first-class tennis players and 10 Tianjin Institute of Physical Education tennis majors as subjects,and tested them at an outdoor tennis court in the Tianjin Institute of Physical Education,a tennis server TUTOR-04 was used to serve the test object,and four cameras JVC CG-P100 were used to take 3-d shots of the subjects’ closed-hand backhand hitting Topspin Ball,the video was edited by Edius software and analyzed by Kwon 3D.Research results:(1)the left shoulder joint of the first-class player in the whole stroke process,the left elbow joint,right ankle joint,right knee joint,right hip joint,right shoulder joint and right elbow joint were significantly higher than those of the special students(p < 0.05).The left wrist joint and right wrist joint were significantly higher than those of the special students(p < 0.01),but there was no significant difference between them in left ankle joint,left knee joint and left hip joint(p > 0.05).(2)the lead time and the hitting time of the first-class athletes were significantly longer than those of the special students(p < 0.05),however,there was no significant difference between the total time and the follow-up time of the first-class athletes and the special students(p > 0.05).(3)the shoulder width angle,right hip angle,right elbow angle and left elbow angle of the first-class athletes were significantly higher than those of the special students(p < 0.05).In the right shoulder angle and its significantly higher than special students(p < 0.01).The right shoulder line velocity x,the right shoulder line velocity R,the left shoulder line velocity x,the left shoulder line velocity R,the left elbow line velocity x and the Left Elbow Line Velocity r of the first-class athletes were significantly higher than those of the special students(p <0.05).(4)the right bowl line velocity x,the left elbow line velocity x,the left shoulder line velocity x,the right shoulder line velocity R,the right ankle line velocity x and the left bowl angular velocity,the left hip angular velocity,the shoulder rotational angular velocity and the hip rotational angular velocity of the first-level athletes were significantly higher than those of the specialized students(p < 0.05).The left bowl line velocity x and the left shoulder line velocity r were significantly higher than those of the special students(p < 0.01).(5)the left hip line velocity Y,the left shoulder line velocity y,the left ankle angle velocity y,the left Elbow Angle,the shoulder width angle,the racquet face angle,the left elbow line velocity y and the left bowl line velocity r of the first-class athletes were significantly higher than those of the special students(p < 0.05).The left hip linear velocity x was significantly higher than that of students of special subject(p < 0.01).The left shoulder line velocity x,the left elbow line velocity x,the left shoulder line velocity R,the twist amplitude and the left bowl line velocity y of the first-class athletes were significantly higher than those of the special students(p < 0.05).The left bowl line velocity R was significantly higher than that of the special students(p < 0.01).(6)the left shoulder angle,right shoulder angle,height of center of gravity,right elbow line velocity x,and left knee angle of the first-class athletes were significantly higher than those of the special students at the end of follow-up swing(p < 0.05).The left Elbow Line Velocity Y,right elbow line velocity Z,twist amplitude,left knee angle velocity and left shoulder line velocity y of the first-class athletes were significantly higher than those of the special students(p < 0.05).The left bowl line velocity x was significantly higher than that of the special students(p < 0.01).(7)The racquet head speed of the special students was significantly correlated with the angular speed of the left knee,the angular speed of the left elbow line and the angular speed of the hip twist(p <0.05).There were significant correlations between the racquet head velocity and the left hip angular velocity,the hip rotation angular velocity x,the left shoulder linear velocity and the center of gravity velocity Z(p < 0.05).Research Conclusions:(1)the power transmission of first-class tennis players and tennis majors is from bottom to top,through ankle joint,knee joint,hip joint,shoulder joint,elbow joint and wrist joint in turn,but a specialist delivers less power than a first-class athlete.(2)the difference of hitting time between first-class tennis players and special tennis players is large,mainly in the lead-racket stage and the hitting stage.There is no significant difference in the waving stage and the whole hitting time.And the specific player will body strength into the ball speed ability is poor.(3)the posture of preparing to hit the ball immediately after the introduction of the racket is not conducive to further increasing the head speed of the racket,and the "causes" are mainly concentrated in the upper limbs,the angular and linear velocity of each joint of the upper limb need to be improved.(4)the students of special events have lower joint linear velocity at the moment of hitting the ball and in the process of hitting the ball,and have not made full use of the power of pushing off the ground.They rely mainly on the hip twist to transfer power to the elbow for hitting the ball,while the first-class players rely mainly on the hip twist to drive the shoulder to rotate power,and then use the power from the shoulder joint to continue to pass down to hit the ball,more in line with the large muscle groups to bring small muscle groups,the proximal limb to bring the principle of the distal limb.(5)the follow-up movement of the special students mainly depends on the left and right lateral swing of the arms,and the racquet is not fully drawn to the upper right shoulder.(6)the students in the special subject hit the instant racquet face angle is larger,but still maintain a certain angle with the ground,although can play Topspin ball effect,but for the ball less friction,topspin effect is not strong. |
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