Fig. 1

Equipment and experimental set-up. a Render of the device with a screen placed in the middle of the two lateral poles, with metal guides where custom-made handles could slide. The motion of each handle was transmitted through a belt and a pulley to a potentiometer that measured its position (left detailed view). Each handle enclosed a load cell (right detailed view) to record the force applied to the handles after fixing them with a screw in specific positions on the guide. The load cells recorded the force applied in the upward direction (i.e., the subjects had to push the handle upward). b Experimental set-up. The device was placed on a table and the subjects were seated in front of the screen. A black curtain was attached to the device in order to prevent the visual feedback of their arms [46]. The arrow shows the direction in which the subjects applied the force during the Experiment 2