The aim of this study is to find the impact instant and than to examine the position of the body segments and angles of the upper arm, during first serve. We have also calculated the post-impact ball velocity, the pre-impact racket centre velocity and its angular velocity too. Data were collected from six right-handed middle and young players during a training session, analyzed with Simi Motion System (50Hz). The impact event resulted more precise with the pre- and post-impact position of the racket centre connecting to the last frame of the fall of the ball after release, using raw data. The post-impact resultant velocity of the ball is lower than the professional tennis players (male 13.5m/s, female 5m/s). The angular velocity of the racket between the two frames of impact is variable by 55.5 to 26.2rad/s. The positions of the body segments show a big variability because we analyzed in and out serves
