The purpose of this paper is to present the response of a human body-seat model to the external disturbance in form of an impulse excitation. A 2-DOF Active Human Body Model with two distinct positions (``back-on'' an ``back-off'') is used in the simulations. Additionally, two different seat types are considered: rigid and passive. Several types of impulse excitations are used ranging in shape, amplitude and disturbance time. A comparison of the results is made: the first on the assumption of equal excitation energy, and the second one for impulses of equal amplitudes but different duration.