Kinematic and Kinetic Analysis of Squat Jump and Counter-Movement Jump

Abstract

This study presents the investigation of maximum height of jump for volunteers executing a squat jump and counter-movement (CM) jump. This analysis was carried out with the help of a 3D motion capture system. The study was aimed at finding out the difference in jumping patterns and jump height for specific groups of participants comprising individuals regularly involved in sports activities and others who rarely take part in a specific sports activity. The ground reaction force (GRF) patterns are utilized in order to analyze both types of jumps. Variation of the maximum jump height in contrast to the knee angle, hip angle and ankle angle was studied. The gait cycle of the jump has essentially four parts: crouch phase, push-off phase, flight phase and landing phase. The change in GRF serves as an indicator for the momentum change of the center of mass. The GRF value decreases at the time of crouch phase and again increases with change in acceleration for counter-movement jump. The decrease in GRF value produces a negative impulse and accordingly negative kinetic energy. In push-off phase a positive kinetic energy is developed which should be more than the kinetic energy developed in crouch phase to attain maximum height of jump. To achieve maximum height of jump the knee angle before take-off varies from 800 to 1000 and the hip angle varies from 700 to 900. Hence at a hip angle of 900 the maximum jump height is achieved according the experimental data. It is observed that moment at the knee angle and hip angle will be maximum for 900 joint angle. Due to maximum moment about the knee and hip joint, jump height attained will be maximum.