FAQs

What are Aqua Knuckles?

Aqua Knuckles are training aids worn during swim practice for competitive swimmers and anyone who wants to move through the water faster (surfers use them, too). Aqua Knuckles are double silicone bands slipped over the ring and middle fingers of each hand. They are sold in pairs and follow ring finger sizing, though many swimmers prefer a snug fit. 

Why should swimmers use Aqua Knuckles?

Training with Aqua Knuckles on a few sets during practice at least every other day makes swimmers faster when they race at meets. Our extensive testing with competitive swimmers indicates that swimmers can shave off as much as .5 seconds per 50 yards.    

How did you come up with the idea for Aqua Knuckles?

I have studied swimming technique as both a competitive swimmer and a coach for decades. There are always ways to improve technique to get faster. Back in 2018, I was watching underwater racing footage of Nathan Adrian and noticed he swims with his fingers slightly spread apart. He swims like this all the way through his stroke (except for his streamline when diving into the water). I then started really paying attention to the finger spacing of the world’s elite swimmers and reviewed hours and hours of underwater footage. Many elite swimmers swim with their fingers slightly opened…using open-finger swimming technique – Katie Ledecky, Michael Phelps and Sarah Sjostrom, just to name a few. 

I felt like I made an exciting swimming technique “discovery” that, if widely known, would help a lot of swimmers get faster. Open-finger swimming technique is not something coaches teach or talk about. In fact, most of us learn to swim by tightly closing our fingers. On my own, I started trying to swim with my fingers slightly opened and figured out it wasn’t that easy. It wasn’t intuitive for me after so many years of swimming with closed fingers. I decided I needed to make a device to teach myself open-finger swimming muscle memory. I tinkered in my garage for almost a year to create a simple but efficient design. I tried different materials, finger spacing, and shapes. With each iteration of the product, I’d go swim a bunch of sets to see how it felt. Finally, in the spring of 2019, I was satisfied with the Aqua Knuckles design. The final design is efficient, comfortable and minimalist with optimal finger spacing. It is also low profile and adds very little drag. My small team of innovators started doing time trials with competitive swimmers to test the final product. It was clear we were onto something that really helps swimmers get faster.

Why does open-finger swimming make you swim faster?

When swimmers pull through the water with their fingers slightly opened (about 5 mm apart), they simulate bigger hands and push more water. Water does not escape through slightly spread fingers because the slight opening between the fingers still obstructs water flow. Spreading the fingers gives the hands more surface area. Spreading your fingers is accomplishing the same effect as wearing paddles to a certain extent. You can’t wear paddles during a race, but you can spread your fingers during a race for a similar effect. The pull is a very important part of the stroke. The more powerful you can make your pull, the more powerful your stroke is. Wearing Aqua Knuckles offers the swimmer the ability to get very precise with his/her finger placement on one of the most important aspects of the propulsion of the stroke – the hand surface area. Using Aqua Knuckles really helps create a precise finger position which can be hard to accomplish otherwise.  There are multiple scientific papers online comparing open-finger swimming to closed-finger swimming. The papers all indicate that open-finger swimming is a better method of generating a more powerful pull by increasing your hand-surface area by as much as 10%. On a side note, we’ve discovered that wearing Aqua Knuckles decreases stroke count also.

Can’t swimmers just spread their fingers on their own?

I tried this myself for a few weeks when I first figured out that many elite swimmers swim with their fingers slightly open. I just wasn’t successful at remembering to spread my fingers as I swam my sets, even for freestyle – let alone fly, back and breaststroke. I have been swimming with closed fingers for a long time. It’s hard to break old habits. I’m an open-minded swimmer with making stroke changes and even I was finding it very hard to spread my fingers without that muscle memory factor. Wearing Aqua Knuckles during practice sets can really help secure that needed open-finger swimming muscle memory across all of the strokes – and throughout the entire pull cycle of the stroke. Even if you have your fingers slightly spread at the catch phase of your stroke, many swimmers tend to close their fingers during the ending phase. If you’re wearing Aqua Knuckles during training, it forces your fingers to stay in the right open-finger position for the entire pull cycle.     

What kind of swimmers should use Aqua Knuckles?

Aqua Knuckles are great for swimmers at all stages. If someone is looking for every possible way to take off time, this is a great tool to try because open-finger swimming might help shave off up to .5 per 50 yards. Young swimmers just starting out can wear Aqua Knuckles to learn this optimal finger spacing technique from the start. Coaches will have a certain relief using Aqua Knuckles with young swimmers because wearing Aqua Knuckles ensures the right finger spacing without the coaches having to constantly remind their swimmers what to do. Surfers can use Aqua Knuckles to make their paddling more powerful also. 

Have you gotten any traction selling these things?

Yes, we have. A lot of our sales come through word-of-mouth…but we also have a number of NCAA D1 teams using Aqua Knuckles. There are several high school teams and many individual competitive swimmers using Aqua Knuckles, too. Masters swimmers also seem to really like Aqua Knuckles, as they’re always looking for ways to get faster and improve. The swimmers and teams most interested in Aqua Knuckles are the ones very “dialed into” technique and how small changes can make big differences. It can be hard for coaches to try new things. New ideas take time to get widely adopted. We’ve been most successful with the teams, coaches and swimmers open to innovations in the sport and new ideas. 


Where and how do you manufacture Aqua Knuckles?

We make them here in California using a combination of 3d printers and silicone molds. 

How did you come up with the name?

It’s just a riff on “Brass Knuckles”. I was thinking about calling them “Practice Bling” but decided Aqua Knuckles is more appropriate.