Biomechanical Analysis Of Male Tennis Players Hit The Bottom Line Of Two Handed Backhand Topspin

In ATP ranked the top ten outstanding top athletes, 90% use two handed backhand batting this technology. Especially athletes in the bottom line of attack,hands slapping topspin is in its high stability, offensive and reliability, is paid attention to by more and more players have become one of the important technical movements.The purpose of this paper is that through the two handed backhand biomechanical characteristics of the bottom line hitting topspin with in-depth research and analysis. Trying to to help athletes to master the technical actions of scientific and effective, achieve the best effect of hitting the most reasonable posture. I hope this article can in tennis teaching and training provided with important significance of quantitative indicators.Methods adopted in this paper is in six national level athletes as experimental object, take telemetering EMG, high-speed camera, three-dimensional dynamometer testing, select the 16 joint points of the human body and five reference point and a point of reference, hand use Ariel APAs software of six subjects sports video digital processing and data analysis; on the other hand the MEGAWIN Mega Win2.4software processing and analysis of EMG test data, draw relevant speed, angle, time and i EMG value results.The experimental results:1, hitting and hitting time at the end of the shoulder angle, the change of.B and E elbow angle left elbow joint angle is relatively small, while the C in the stroke, the changes of left elbow joint angle is relatively large, A and F left shoulder angle in hitting time to hit the end of the day, the left elbow angle respectively. Reduced 45.36 degrees and 41.06 degrees, while D left elbow angle reduced only 25.01 degrees.2, the racket to hit muscle discharge process, 12 muscles showed a left anterior deltoid, left rectus femoris at this stage only a weak fluctuation; the left biceps, right rectus femoris muscle, right trapezius muscle, gastrocnemius muscle and rear right deltoid muscle with proper fluctuation; the left biceps, right trapezius muscle, right deltoid muscle waveform is the most intense. The moment of contact with the ball to play with the end of muscle discharge process, 12 muscles showed the left brachioradialis, left biceps, right deltoid muscle is muscle force; the right rectus femoris, left rectus femoris and left abdominal external oblique force is relatively small; the left anterior deltoid, right gastrocnemius and right anterior tibia only the relative muscle force.3, a whole process kinetics of the.E right foot were significantly different from Cand B, and the peak value of E before the other two subjects, and then slightly decreased.A foot stress trough peak change obviously, clear, clear the right action; D negative force is relatively large, after the trend gently. And there is no obvious peak;F force order before the right foot, then decreased gradually. The whole process of hitting the stage left.E kinetic results on the vertical shaft force is firstly increased and then decreased after B and is gentle;In the vertical direction of the force is increased first and then decreased, but reduced to the last moment is still in the initial stage is positive and negative; C curve is first increased and then decreased, the decrease of.A curves increases slowly first gradually increased, then gradually increased, the peaks and valleys; curve D started from negative in the initial stage, the first increase and then decrease gradually, but the decline was not more than negative; F curve increases first, then decreases, but slow and flat, slightly undulating.Through the statistics of the relevant experimental data analysis in kinematics,EMG, and dynamics of the conclusion.Conclusion:(1) the kinematics of backhand topspin hit the bottom line in the upper limb abduction and pronation muscle contraction of the racket outside acceleration plays a major role.(2) the racket in the upper arm adduction and internal rotation, can obtain more elastic energy, which hit a topspin more fast and powerful.(3) to a low center of gravity of body attitude, not only through the tennis movement is always predict the precise positioning, timely coordination of body force, accurate balls hit to guarantee.Conclusion:(1) the maximum EMG racket to the moment of contact with the ball, the left brachioradialis, left biceps, right deltoid muscle is the main force of upper limb muscle, gastrocnemius muscle and right posterior tibialis anterior muscle of lower limb as the main force muscles, left and right abdominal trapezius muscle trunk main force muscles,(2) the moment of contact with the ball to play with the end part, the left brachioradialis, left biceps, right deltoid muscle force is the main muscle groups.Conclusion: the dynamics of foot force order should be left to the right, there are obvious changes in body weight, reduce the waiting time for action.