Using the HO model to obtain the impact force of real climbing ropes as a function of fall height h and climber's weight mg, one must know the experimental value for E of a given rope. However, rope manufacturers give only the rope’s impact force F 0 and its static and dynamic elongations that are measured under standard UIAA fall conditions: A fall height h 0 of 2 × 2.3 m with an available rope length L 0 = 2.6m leads to a fall factor f 0 = h 0 /L 0 = 1.77 and a fall velocity v 0 = (2gh 0) = 9.5 m/s at the end of falling the distance h 0. The mass m 0 used in the fall is 80 kg. Using these values to eliminate the unknown quantity E leads to an expression of the impact force as a function of arbitrary fall heights h, arbitrary fall factors f, and arbitrary gravity g of the form: