Fins can be a great training aid for when your upper body is either injured, or you want to ease into your swim workout.

2. Increases overall strength and endurance in your legs

Fins are tools of resistance. Your legs contain the biggest muscles in your body–that added work means that they are getting a harder workout, something that is perfect for increasing overall power and conditioning.

And lastly, for swimmers who prefer to dangle their legs limply behind them like kelp as they swim along, fins generally help boost the cardio/aerobic nature of their work. Not kicking when you have fins on your feet generally leads them to sinking, so by nature of maintaining any kind of forward propulsion you have to kick.

3. Easier to hit the upkick

Our coaches are always telling us to work on the upwards phase of our kick, but it can often feel a little weird. We’ve become so accustomed to kicking downwards—which is a much more natural kicking motion—than kicking up, which leaves us feeling disjointed and awkward.

The added surface area of fins helps you really feel out the up-kick.

If you really want to work on your up-kick throw some vertical kicking into your practices—you’ll come to appreciate how important it is when kicking vertically, especially with dolphin kick.

4. Uh, using them is really fun?

Swimming with fins is fast and fun. Flying under and across the water, whether dolphin kicking or swimming, at lightspeed is quite pleasurable.

The speeds we attain are higher, the wakes we create are massive (sorry-not-sorry swimmers in the next lane!), and we get to swim at paces we rarely are able to when straight swimming.

Simple as that.

5. They help improve ankle flexibility

The importance of ankle flexibility for swimmers is hard to understate, and is one the most important factors in having a deadly kick. A low range of motion in your feet means that you are kicking water downwards, as opposed to kicking water backwards.

A reason a lot of triathletes and newbie swimmers have such horrendous kick is because they have next to no range of motion in their ankles.

When we are wearing fins you come to understand this—the extra surface area extending to the tip of them provides additional ankle extension and surface area to plant into the water to push you forward.

Fins put your feet into a position where your ankles are largely forced to be pointed/extend, which will help improve overall flexibility in your feet.

6. Improved body position

If you are using the fins to kick, and not simply dangle behind you, your body will ride higher in the water. It gives you that amazing feeling of skimming across the surface of the pool.

This effect is especially noticed in swimmer’s whose kick isn’t very strong, and therefore tend to sag and bulldoze their way through the water.

Fin-powered swimming shows you the body position you want to attain during your regular swimming and reminds you how crucial it is to work on your kick.

SWIM FINS: THE DOWNSIDE

1. They can become a crutch

The swimmers who scramble for fins the fastest are usually the ones with the worst kicks. They become dependent on the tool, and can hide their shoddy ankle flexibility behind the raw quad and hamstring power we rely on with fins.

You will never catch up to your fast-kicking teammates by always reaching for the fins every time a kick set comes up.

2. Blisters

I’ve gone through dozens of pairs of fins over the years, and some of them have left some truly unsightly blisters on my feet.

Not fun.

How to Choose the Best Swim Fins for You

Picking out a pair of swim fins seems like a no-brainer–pick out the biggest, baddest pair of the bunch!

But if you want to make the most of this piece of swimming equipment, and want to avoid getting bruised heels and blisters, than here is what you need to know about picking out a pair of swim fins for yourself.

1. Length of the fins.

When it comes to training with fins, length is the most important thing.

But probably not for the reason you think.

Fins might all look the same, but they should serve a function beyond just going fast. They should match up to what kind of training you are doing. While we all scramble for the long fins because in our minds long = much faster, this isn’t necessarily the case. The longer your fins, the more difficult it is to kick with any kind of turnover. (Longer, stiffer fins are best used for snorkeling and diving, not swimming.)

If you take one thing away from this guide, remember this: long fins will collapse your kick frequency.

In summary:

2. Open heel vs Closed Heel.

Until recently almost all swim fins designed for competitive swimmers had closed heels. More and more now we are seeing fins that have the open heel, with a strap going around the ankle to keep the fin in place.

Personally I much prefer the open heel fins, as it will usually provide you with a fuller range of motion.

The problem with really rigid fins that have closed heels is that if you have decent ankle flexibility the top of the heel will dig into your Achilles when you are kicking.

In my experience these type of fins also stay on the foot much better, which comes in handy when you are kicking all out, or pushing off the wall.

3. Stiffness of the fin.

Another important thing to consider when buying a new pair of fins is how rigid they are. For this reason, I would recommend that you either get your hands on a pair you are thinking of buying to assess the stiffness for yourself.

Zoomers, for instance, one of the most popular set of fins you will find in a swimmer’s bag, are quite rigid and unforgiving. Most diving fins are similarly rigid, made of a hard plastic.

The more stiff the fins, the harder it will be to kick.

While a stiff fin may be useful for getting fit, or getting a harder workout out of your legs, they promote a slower tempo kick, which doesn’t benefit swimmers who are trying to get faster.

Additionally, really stiff fins tend to dig into the top of your heels as mentioned in the previous point.

4. Sock or not to sock.

One of the things that drive me nuts about using fins is the blisters that sometimes come with their usage. To combat this as an age grouper our coaches had us bring old cotton socks to put on to help mitigate some of the rubbing.

Nowadays there are all types of socks designed specifically for this purpose.

If you are using a more rigid, rubber fin I would recommend getting a pair of socks if you are going to be doing substantial training with your fins on.

5. Silicone vs. rubber.

More and more high performance fins are being made with silicone these days, and thankfully so.

Silicone rubs and blisters your feet a whole lot less than rubber, which means that you can kick to your heart’s delight without worrying about destroying the skin on your feet. The suppleness of silicone also promotes a more fluid and natural kicking motion.

So there you have it, a comprehensive guide to the benefits of fins, short vs long fins and silicone vs rubber fins.

See the full post and more from Olivier Poirer-Leroy here