When pulled by the tail, rodents instinctively grab anything they can, to try to stop this involuntary backward movement, until the pulling force overcomes their grip strength. when positioned in front of the GSM bar, or trapeze, or grid, the animal grasps at it.
After the animal loses its grip on the grasping bar, the peak amplifier automatically records and stores the peak pull-force achieved by the limbs and shows it on the display.