All it took was watching the tail fins of fish ? except that we couldn't keep up with them because our traditional fins took too much effort. Using hard kicking paddle fins can result in leg strain, fatigue and cramping. Because of the kick resistance of a paddle fin, divers often ?felt? like they were moving fast. But underwater speedometers proved that these divers were actually moving relatively slow. SplitFins deliver more propulsion with less drag and kick with less effort. Reducing the stress and strain of the kick results in greater sustained speed, power and comfort. Independent testing has also confirmed that the SplitFin design significantly reduces air consumption.