Get a Fitted Jump Rope - Nothing makes the Double Under more difficult that when you constantly change equipment. Grabbing one of the jump ropes off the Wall at the local box is only going to take you so far. Too short a jump rope and the rope won’t make it under your feet. Too long and the cable hits too far in front slowing the speed of the rope. Here's a quick guide for cable length: For those at 5'6" height and less, add 2'10" to your height. For those over 5'6", add 3'0". With proper hand and arm position, these cable lengths will get you off and running. We list this step first because it's the most important. Do everything else right but have a too short or too long a rope and it won't matter.