With a view to improving the athlete's performance during the javelin throw, the objective was to develop, based on the application of Newtonian mechanics to the javelin flight process, a mathematical model and a computerized tool that make it possible to determine the influence on javelin flight trajectory and distance of the characteristic parameters of throwing release phase. As a result, a mathematical model and software were obtained that make it possible to predict the trajectory and flight distance of the implement in function of the properties of the javelin and ambient air, gravitational forces and initial throwing parameters. The model was validated by comparing the flight distance predicted by the model with experimental results obtained in the framework of this research, as well as with data obtained from international competitions. The mean prediction error obtained during the comparison of the javelin flight distance calculated with the model, with the actual throwing results, ranged from 0.65% to 1.58%.