The purpose of this study was to investigate the kinetic and kinematic factors of the difference in jump height of layup shot between takeoffs with the dominant and non-dominant legs. Thirty male collegiate basketball players performed layup shot jumps (LSJ) with the dominant and non-dominant legs. Three-dimensional positions of the markers attached to the body landmarks and ground reaction force (GRF) of the takeoff legs were measured with a motion capture system and force plates, respectively. Based on these data, jump height, impulse of vertical GRF during the push-off phase (from the instant of lowest position of center of mass to toe-off) and mean vertical GRF were computed. Furthermore, kinetic and kinematic variables of the hip, knee and ankle joints were calculated during the push-off phase. The results showed that the jump height and vertical impulse of LSJ with the dominant leg were significantly greater than those of LSJ with the non-dominant leg. The mean vertical GRF tended to be larger in LSJ with the dominant leg than that with the non-dominant leg. The mean knee extension torque of the dominant leg was significantly greater than that of the non-dominant leg. However, there were no significant differences in kinematic variables between the dominant and non-dominant legs except for the peak angle of ankle dorsiflexion. The results suggest that the side-to-side difference in jump height of LSJ was attributable to the mean knee extension torque during push-off phase.
