THE INFLUENCE OF LOWER AND UPPER EXTREMITY JOINT MOVEMENTS TO THE SERVICE SPEED OF NON-ELITE TENNIS PLAYERS

Abstract

Since the service initiates every point in tennis, it is logical to assume that the stroke greatly influences the outcome of a match. A wealth of research has been conducted on the services of elite players, however, currently a paucity of data has been provided on non-elite service kinematics. The purpose of the present study was to quantify how lower and upper extremity joint movements influence the service speed of a non-elite tennis player. Five male tennis players were videotaped performing high velocity serves using two 50 Hz video cameras (Sony HVR-Z1E, Sony, Japan). Video clips were then manually digitised using Peak Motus software (Peak Motus 9.0, Vicon, Los Angeles, CA), to calculate joint angular velocities, horizontal racket velocities and joint angular displacements. Peak angular velocities and impact racket velocities were then inputted into the Statistical Package for the Social Sciences (SPSS, Inc) software, in order to test for relationships and the magnitude of impact racket velocity that may be explained by each joint motion. The largest influencers of impact racket velocity were shoulder abduction and horizontal flexion (23.4%) and wrist flexion (33.2%). Shoulder abduction and horizontal flexion observed a significant positive correlation with impact racket velocity (r = 0.422, P < 0.05), whilst wrist flexion showed a strongly significant positive correlation (r = 0.626, P < 0.01). The later occurrence of peak pelvis rotation velocity than that for upper torso rotation and shoulder abduction and horizontal flexion, identified that a complete proximal-to-distal sequence is not present in non-elite tennis service. Findings from this study indicate that whilst improvements in wrist flexion and shoulder abduction and horizontal flexion will enhance racket velocity, improvements in internal shoulder rotation are more beneficial for attaining a higher level of service performance. Thus, a key focus for non-elite players is to condition their core and upper body musculature and improve biomechancial technique, in order that higher velocities of internal shoulder rotation may be generated without increasing the potential for injury. Future investigation is needed to determine if different service kinematics exist between genders at the non-elite level and therefore, the type of development programme best suited to each gender for improving service speed.