I dont think there are really any "jumpers" at all. The only jumper we know of was the one jumping from a higher position who jump across and down through the window. Imho its not a jumper as in a z'd jumping from say the ground up 5 stories or something. Burt only yelled jumper not to name the type of z'd but as a verb, what the z'd was doing. My 2 cents on the "jumpers".