In manual wheelchair locomotion, the large upper extremity loads and the repetitions of the propulsion movement increase the incidence of upper limbs injuries, pain and muscle fatigue. The main goal of this study was to investigate the influence of a closed-loop partial power assistance for manual wheelchairs through predictive simulations of a dynamic four-bar model. The applied control law applied can be seen as an impedance-like control, but it does not require force measurement. The simulation results indicate that this strategy can reduce joint torques without significantly altering the typical kinematic pattern of manual wheelchair locomotion.