We examined the influence of the mechanical work done by the lower limb joints and segment rotations on the mechanical energy of the center of mass (ECoM) during three take-off phases in the short approach triple jump. A motion capture system and three force platforms were used to collect the three-dimensional markers and ground reaction forces during the three take-off phases from eight male triple jumpers. ECoM decreased during the step and jump phases, whereas ECoM increased during the hop phase. The change in ECoM during the jump phase was significantly correlated with the net mechanical work done by the knee joint torque. The increase in the vertical component of ECoM due to the stance leg thigh rotation during the step and jump phases was significantly lower than the hop phase. The knee joint torque contributed to the mechanical energy inflow on the stance leg thigh, and it led to an increase in the vertical component of ECoM. These findings imply that triple jumpers are required greater lower limb joint torque production, especially knee joint torque, to produce thigh rotation and maintain the mechanical energy which was obtained during the approach sprint.