The open water swimming stroke is different to pool swimming stroke, and the kick is one of the biggest differences. the legs contain the biggest muscle groups in the body and are capable of burning a huge amount of fuel and oxygen, but unfortunately for swimmers they are very bad at creating propulsion. This makes kicking an inefficient way to gain swimming speed especially for long distance.
You may see sprint swimmers ‘turning on the afterburners’ in the pool, and many rely on their kick for a lot of there speed, but the inescapable truth is that the speed is not sustainable. Even if you are gifted with size 17 feet and loose ankles a big kick is not sustainable over long distances. And for the triathletes out there having a low energy kick is a huge advantage in saving the legs for the bike and run.
The other difference is that open water swimmers have a lot more buoyancy (either from a wetsuit or from more dense salt water) so the legs naturally float higher in the water. This makes open water swimmers more streamlined without having to rely on a big kick to lift the legs up.
So what is a good kick for open water?
Well for some almost no kick at all is needed for the legs to happily cruise along on the water, especially if wearing a thick wetsuit. For triathletes this is ideal..
For the rest of us a well timed 2 beat kick (one kick for each arm stroke) will be sufficient to give good balance and keep the legs streamlined. A two beat crossover is a variant of this that takes a little longer to master.
A four beat or six beat is ok if you find it sustainable for longer distances, everyone is different. But there is a good chance you are wasting a lot of energy for not a lot of propulsion, and spending some time developing an ‘open water kick’ could be time well spent.