Kinematics of lower extremity in tennis flat and spin serve

The purpose of this study was to explore the biomechanics of the two different serving patterns - flat serve and spin serve. In conjunction with force plates that helped to measure the ground reaction force (GRf) and worked out the center of pressure (COP), a motion analysis system was used to discover the 3-D kinematic changes of the ankle, knee, hip, pelvis and trunk in the overall serving motion in the study. The moment formed by COP with the whole body center of mass would then be analyzed to investigate the kinematic characteristics of the body. The further understanding of the role of joints in the lower extremity during a serve will provide a reference for motions and techniques of training and teaching, with views to improve serving efficiency and to avoid sports injury.