GOOD NEWS: using fins can accelerate training

BAD NEWS: being addicted to fins can lead to lazy legs and body position

NEWS FLASH: to get the most out of fins the trick is knowing when to hold'em

Fins can kick things up a level in training but using them every lap of every session means you aren’t doing the work and those laps may be going to waste. Start by choosing the right fins for the job and to use them to support and enhance your training. Not all fins are created equal. Here’s a quick crash course:

Long fins are over 63cm long and short ones are under 63cm. Longer fins generate more thrust because they move more water with each kick. Moving more water also means you need more power to drive them. If your kick is weak or your kicking technique is incorrect, then you won’t get the benefits of the long fin’s thrust efficiency.

Fins also have different levels of flexibility. Those that have a lot of flex can “scoop” the water and add snap to the kick. But stiffness is also necessary for applying force to the water in the first place. Fins need to hit a “sweet spot” between too stiff and too flexible. Too stiff and the fin will take too much energy to move and won’t “scoop” and “snap” the water effectively. Too flexible and there will be very little thrust.

The sweet spot has a lot to do with the length of the blade. Because long fins need to move more water, they experience greater resistance from that water. A stiffer blade can handle that resistance without bending overmuch. However, the same stiffness on a short blade would be inefficient. Conversely, the ideal flexibility for a short blade would make a long blade too floppy to be effective. It sure is a finicky equation!

How firm the fin is also depends on the materials it’s made from. Fins used to be made from natural rubber. Today, some are still made from rubber but a lot are molded from silicone and thermoplastic elastomers (silicone-plastic hybrids). Silicone gives modern fins a suppleness that not only improves the fluidity of the blade’s movement, but also makes for a more comfortable foot pocket. Thermoplastic elastomers are also very versatile and can be engineered with varying stiffness even along the same blade. Conversely, natural rubber is harder to precisely engineer, is less comfortable on bare skin, and is prone to hardening and cracking over time.

Fins improve ankle flexibility due to the extra force placed on your ankles as you kick. The increased ankle flexibility delivers a more efficient flutter and improves kick speed. And when used with appropriate sets it is a great way to step up strengthening of the core and legs, as well as promoting an optimum body position in the water.

The EDGE FIN is an allrounder that builds core and leg strength. Its specially-designed side-rails help activate the hips and quads.  The Edge is also a silicone fin so it will mold to your feet after a number of sessions.  The fit is ideal for those with wider feet and toes that need a bit of space.
 
The innovative POSITIVE DRIVE FINS work for all four competitive strokes. Yes, even breaststroke and that is why they are often referred to as breaststroke fins. These fins have a unique ellipsoidal blade that promotes correct propulsion for any of the strokes. The asymmetrical shape and adjustable heel strap allow the swimmer to safely build power in the breaststroke kick. The short and wide blade promotes a natural inward supination kick style for backstroke, butterfly, and freestyle. These fins increase leg strength, foot speed, and ankle flexibility for all four strokes, which makes them a great tool for training the individual medley.

The traditional LONG FLOATING FIN can be the biggest cheat in the pool. The long hydrodynamic blade promotes slow kicking style while adding propulsion and lifting the body position high in the water. While strengthening the leg from its use, these fins can easily become a crutch that carries legs through the swimming session. That doesn’t mean that long fins are evil. When used as a training tool they help swimmers learn propulsion in the flutter and butterfly kicks with the longer kick encouraging the use of the hips for propulsion.
 

 
The FOIL MONOFIN is an amazing training tool which deals with both the up and down kick equally, creating a powerful undulating motion to the dolphin kick. This fin was made popular by coach Bob Gillett and his most famous pupil Misty Hyman, 2000 Olympic Gold Medalist in the 200m butterfly.
 
Here's some ideas on how to put fins to work on your kick technique:

It’s hip!
The key to kicking with fins properly is to move your legs at the hip. 
Your knee should bend only slightly on the down stroke.
Focus on keeping your movements slow and smooth, and ankles flexed.
If you’re kicking properly, you’ll notice that you need to do very little with your arms, which you should keep at your sides or gently clasped in front of you.
This hip-generated leg movement will encourage the water you displace to run off the edge of your fin blades and out behind you in a jet stream.

No knees!
Knee kicking generates a lot of turbulence, which means displaced water is moving downwards and outwards, not just backwards.
Excessive turbulence decreases your thrust efficiency because less of your energy is contributing to forward propulsion.
For most folks, the down-stroke of the flutter kick is more powerful, while the up-stroke is weaker.

This is because people in general have weaker back muscles on their legs (glutes, hamstrings) relative to the front thigh muscles (quads).
Add stiff hip flexors to the equation and you have the perfect recipe for imbalanced kicks!

Need a hand? Our innovative equipment is designed to help you get more out of the water but sometimes it is hard to know what to use, when and how. Reach out to our Aussie Team anytime for help, tips and insights: www.finisaustralia.com.