Surge Jump Rope 6-7 jumps a second This is our newest design! Top End jump rope used by many of the top jumpers in the world. Made specifically for speed and double unders. The metal handles are very light and easy to control. The shape of the handles allow for comfort and control. Extremely Durable and Fast. Use only indoors or on a protective mat. The Science Behind The Surge Jump Rope Feels like the rope turns itself. A jumper is trying to produce rotation in the handle’s axle. He does this by moving the handle in a circular motion with the cable trailing behind. This puts tension on the cable creating the centripetal force that causes it to rotate around the handle. This motion permits the jumper to move her hands in more of a reciprocating (up and down) motion rather than a circular motion by implementing theories of a crank mechanism. It our belief that this causes less fatigue, can produce faster rotation, and allows the jumper to maintain a more consistent speed (assuming that maintaining a consistent pace in a reciprocating motion (like drumming) is easier than while in a circular motion). The advantage to having two bearings is that it handles the axial load much more efficiently. With 1 bearing, there is the addition of detrimental axial torque. The added axial torque on the bearing will cause it to wear out faster, and adds friction so it spins less freely. Radial bearings are not designed with axial torque in mind. It is assumed that they will take only axial load and/or thrust load. Overall, the design causes the handle to be very rigid and feel ‘solid’ in your hand.