We study the influence of realistic forces based on (Dirac - )Brueckner theory on the dynamics of heavy-ion collisions in the framework of two models; in the relativistic Boltzmann - Uehling - Uhlenbeck approach and in quantum molecular dynamics. These forces are compared to phenomenological forces, either a Skyrme interaction or the nonlinear Walecka model. Analysing the rapidity distribution and flow observables for semicentral Ca + Ca collisions at 400 A MeV, both models show a strong enhancement of the flow with realistic forces relative to phenomenological forces.