Determination of the optimum objective function for evaluating optimal body and barbell trajectories of snatch weightlifting via genetic algorithm optimization

In this paper, we present the optimum objective function for snatch weightlifting using genetic algorithm optimization. Therefore, it would be possible to study snatch weightlifting more accurately, because the biomechanical parameters in this movement including the body trajectory and forces and torques acting in the joints, depend on the objective function. In this study, kinematics and dynamics equations of movements and three well-known objective functions as total kinetic energy, total torque and total power for biomechanical model of weightlifter using Lagrangian formulation have been obtained. In the results the optimal body trajectory has been obtained using mentioned three functions separately as objective functions and kinematics, dynamics, maximum tolerated torques and balance maintenance equations as constraints and also the barbell trajectory as input to optimization algorithm. The optimum objective function has been presented comparing the three analytical trajectories and the experimental trajectory, which has been calculated using infrared camera. The optimization showed us the trajectories generated by total power have the best convergence to the experimental trajectories.