text: Think.  \n\nStatic - put weighing scales on treadmill.  user stand on, measure the static force applied to the treadmill.  (which will be equal to the user's weight, so I can't see the point in that one....)\nDynamic - put the scales vertically in front of user, supported on a wall or similar.  The force exerted forwardly by the user pushing on the scales will be equal to the reaction force between feet and deck.\nYou could also mount strain gauges on the deck frame.  Check out readings for stationary and in-use times.