By kicking against a load that provides for a separate power and recovery cycle as opposed to the traditional power-power cycle of other fins, oxygen depletion is reduced, the legs and body work more aerobically and less anaerobic ally, and swimmers can maintain their workout efforts for longer periods of time. Independent research has shown less lactic acid buildup (lactic acid is the proof of anaerobic activity) and more oxygen absorption with Force Fins. Flat fins bring on symptoms of fatigue and cramping more quickly.
Other fins, flat fins want to go through the water along the path of least resistance, which is sideways! Don't believe it? Hold a flat, heavy object at the surface of the water, let go and watch what happens. It turns on its edge and heads for the bottom. Or, if it's light like a sheet of paper, it will zigzag or "dish" its way down. Neither action is going to help your kicking. With flat fins - even small or cutoff flat fins - a swimmer is constantly fighting all this twisting and torquing, and any effort spent this way is wasted.
The curves and flexibility of our blade design help keep the legs properly oriented for more efficient power, even as they fatigue.
FORCE FINS or SLIM FINS?
Force Fins are our original design, and being somewhat larger than Slim Fins, they provide a more concentrated leg workout (more resistance). They are a more versatile fin, in that they can be used for other sports, such as snorkeling, SCUBA and float tube fishing. From a swimming perspective, they are a very specific training tool and are excellent for butterfly, "new-wave" breaststroke, and the backstroke dolphin kick.
Slim Fins are narrower than the Force Fin and are specifically designed for pool swimming - especially freestyle - applications. With Slim Fins, the blades don't touch, flip turns are no problem, and high stroke turnover or cadence is easily maintained. Slim Fins can be used either while swimming or in kicking-only drills. They receive the highest recommendations from swimming coaches and professionals, and will do the best job for and are probably the best choice for most swimmers.
How they are made?
Manufactured in the USA and backed by 20 years of research and development, Force Fin swimming fins are made of ultraviolet-, abrasion- and chemical-resistant polyurethane and heat-treated for 16 hours at temperatures where other fins melt. This process allows the molecules to cross-link giving the blade its snappy, high-performance characteristics and extreme durability. Unlike other brands, Force Fin swimming fins will not melt on hot pool decks or mark the sides of pools, and should last season after season, even when used daily. We could go on forever describing the unique benefits of using Force Fin swimming fins to improve your swimming.