Here's a simple idea. Replace the human pusher with a hydraulic press that will apply a horizontal force to the chest of the person being pushed that is of equal magnitude to the human's push. The human's push will go from zero to some maximum over an interval of time. Have the force of the press increase over an identical period of time until it reaches the maximum.
Will the results be the same?
Yes, if you can duplicate the mechanics of a human push exactly - they're quite different from a hydraulic press, so it's not the same test.