Review
Measuring power is nothing new in the world of cycling and running, but in swimming it’s still relatively new. Only recently I read more about Smartpaddle: a new piece of technology that (finally) makes it possible to measure power in swimming. Awesome! But wait..
Does swim power matter?
Does it actually make sense to measure power in swimming? Swimming is not only about producing high power numbers, right? As stated in a 2013 research: “Nowhere in sport is performance so dependent on the interaction of the athlete with the surrounding medium than in swimming.” To go fast, we need to push against the water. But pushing harder does not always equal going faster. “Swimming comes down to high stroke efficiency at a high rate while simultaneously minimizing drag.”
In other words, if you want to go fast, power alone does not tell us the whole story. This is exactly what former engineer at Nokia, Riku Rimpelä thought. The Finnish CEO of Trainesense created Smartpaddle, the first force measuring wearable for swimmers.
Swim power with Smartpaddle
Smartpaddle is not the typical power meter cyclists now. It is actually way smarter. It does not only give insight into the absolute forces produced in the water, it also shows whether you push at the right time and in the right direction. Not producing continuous power means losing pressure against the water. Not producing power in the right direction lowers stroke efficiency.
Step 1 collecting data with Smartpaddle
Using Smartpaddle is easy. You simply put it on your fingers with rubber bands and start swimming. Once you are interested in your data, you can transfer it to your mobile app within a couple of seconds via Bluetooth. The data is shown on your mobile device or laptop. That is where the next step starts: understanding the data. This can be a challenge, but let’s give it a go. Stick with me and let’s look at 3 example graphs.
Step 2 understanding Smartpaddle’s data
Here are 3 graphs that I personally find most interesting:
You are looking at the force (y axis) produced by your hands over time (x axis). The green line shows horizontal produced force which moves us forward. The red line shows vertical force that lifts the (upper)body up. The yellow line is force produced to push water sideways. To quickly summarize: “green force” is the force we want and “red force” should be minimized for an efficient stroke.
So far so good. Once you manage to minimize your red force and maximize your green force, the challenge is to keep up the good work when getting fatigued. That’s when a stroke comparison comes in handy.
You are now looking at stroke to stroke variations in a stacked bar chart. This graph does not only show a difference in swim stroke efficiency (green vs red), but also in total force (bar height). We want a high swim stroke efficiency, even when getting tired at the end. We also want to minimize variation in total force between strokes to keep the speed as constant as possible, because acceleration costs extra energy.
On to the third and last graph. The smart paddle measures acceleration, pressure and position. Therefore, it is possible to plot a graph in which you can see the movement of your hand through the water. At the top left the hand enters the water. Then clockwise it goes to the front into the glide phase, and then drops in depth when getting into the pull phase.
This graph can tell us a little bit more about a possible cause for “red forces”. You can see the hand first getting deeper into the water after entering the water. Than at 80 cm (x axis 0.80) after the entry point the hand is going up. This will not only result in sinking legs and therefore increased drag. It will also be more difficult to transfer from glide phase to pull phase without first creating “vertical red force”.
Step 3 using data to swim faster
Although the amount of data can be overwhelming, I think with a little help and patience you should be able to understand the data Smartpaddle provides in the app. Understanding the data does not immediately mean you also know how to fix certain numbers. You will need some experience for that. This is when a trainer or coach comes in handy. Only when adding step 3 (using the data) to step 1 and 2 (collecting and understanding the data), smart paddles can become a way to improve your results instead of being just a cool gadget. That is why I would recommend using this piece of technology only when your trainer is interested as well. If not, you can of course become an expert yourself as well, by doing one of Smartpaddle’s courses.
Smartpaddle costs €499 and works with a license model. That means you will also need a license which costs about €10-€20 per month depending on the subscription. 
Extra sources: Fastlane4 & Smartpaddle
Would you like to read more reviews? Check out all reviews!
Founder of Molab, Human Movement Scientist and Freelance Content Marketer.