Once again, Speedo hit the mark with their Biofuse Fins. These zippy, silicone fins are likely one of the best strength training fins on the market.
The name “Biofuse” reflects Speedo’s melding of both soft and hard silicones into one cohesive design. Because of this unique use of materials, the Speedo Biofuse swim training fins fit the foot properly with no adjustment necessary. The Biofuse really lives up to its name in that it doesn’t feel foreign to wear. I found the foot pocket to be as comfortable as advertised without any slippage.
This fin was created specifically to maximize the wearer’s leg strength and kicking speed. As mentioned previously, the stiff, short blade encourages quick, short kicks in order to keep the legs afloat. As a result, proper kicking tempo is promoted and paired with proper arm technique.
Also, the stiffness of the blade makes for a more powerful stroke. Just as physics suggests, the stiffer blade requires more leg strength to move through the water; however, it also delivers more vigorous propulsion than many other fins, especially when used in conjunction with the flutter or butterfly kick. In other words, this fin will require a decent amount of work to use effectively, but the return on your kick more than doubles the efficiency of the stroke. Unfortunately, the Biofuse fins are not quite as efficient when it comes to the breaststroke. Although the rounded tips of the blade make it somewhat easier, they are simply not designed to handle such a kick.
I found this fin to be somewhat similar to the Speedo Optimus, save for the material. While the Optimus is made of all-natural rubber, the Biofuse is made from silicone. Although I have nothing against the durability or performance of silicone, I find it to be somewhat abrasive against my skin. For this reason, the Speedo Optimus still tops my list of favorite Speedo swim fins. Overall, the Biofuse training fin is highly versatile, well-fitting, and stylish.
This fin comes in a variety of sizes (XXS-XXL) based on shoe size.