The Nemesis Fins are made from buoyant EVA foam instead of rubber, and aren’t just designed to increase your kicking power. The shape is actually intended to give your body a nudge into a more efficient swimming positions, which should make you go faster. That’s not to say you won’t get more of a boost from each kick, though. The channels and square holes along the surface of the flippers increase the amount of water you displace with each kick. Speedo isn’t talking about the specifics of how that happens just yet.
Humans aren’t really ideally suited to move through water at a great speed. We’re kind of bulgy in the wrong places and have entirely too much hair. Have you ever watched an Olympic swimmer slicing through the water, then noticed people literally walking alongside the pool keeping pace? The top speed for human swimmers is about five miles per hour. The humpback whale, on the other hand, can shoot through the water at upwards of 16 mph, and they are huge. If that fin shape works for them, there must be something to it.
These fins won’t instantly turn you into a world-class swimmer, but they’ll probably reduce the amount of energy you have to expend to some degree. Speedo’s Nemesis Fins will be on sale soon for $40 retail. Don’t expect to beat any whales in a race, though.