Biomechanics Analysis of Arm Flexion Isometric Force, Upper Extremity Movement, and Ball Toss Position Towards Ball Speed in Tennis Flat Serve

Abstract

This study analyzed arm flexion isometric force, upper extremity movement, and ball toss position toward ball speed in tennis flat serve. Nine tennis players aged 20.78 ± 5.044 years old participated in this study and were chosen as research samples by using the purposive sampling method. The independent variables of this study were arm flexion isometric force, upper extremity movement, and ball toss position. The kinetic data were collected by Force Decks by Vald Performance, and kinematic data were analyzed by Kinovea 0.9.4 computer software. The dependent variable was ball speed which was measured after the impact with racket by using Bushnell Velocity Speed Gun type 101911. The data were analyzed by using descriptive analysis and Kolmogorov-Smirnov normality test in SPSS statistical software. Furthermore, multiple linear regression was performed to find the correlation between variables. As a result, all of the data were in the normal distribution. The kinetic data were analyzed by using the descriptive method. The mean of arm flexion isometric peak force was 131.22 ± 41.27 Newton, arm flexion isometric average force was 121.44 ± 42.08 Newton, and rate force development was 270.33 ± 112.88 milliseconds. The kinematic data were also analyzed by using the descriptive method. The mean arm flexion and ball height in ball release position were 120.39 ± 14.65 º and 165.76 ± 25.39 cm. The mean peak ball position was 337.08 ± 23.92 cm. At the ball impact position, the mean of the hip torso, arm flexion isometric, and ball height were 30. 46 ± 15.42 º, 186.93 ± 14.43 º, and 258.77 ± 26.51 cm. The mean ball speed was 80.23 ± 16.38 km/h. There was a significant correlation between ball height in peak position and impact position (R Score > .666). Furthermore, kinematic had a significant correlation with ball speed (R Score > .666).