Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In



Ask A Gear Guru: What Are Some (Other) Ways To Measure Effort In The Water?

While 99% of pool workouts are time/distance based, we look at a few alternative options and the gear you’ll need to help make you faster.

Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app.

Everyone knows that big, old clock sitting on the side of the pool deck. The one that moves double-time during your rest interval and looks like it’s wobbling a little bit after your 6×200 main set? If you’re a triathlete who trains in the pool, there are times when you probably feel like a slave to that thing: It tells you when to go, it tells you you’re ahead or (God forbid) behind on your interval; it tells you that, hopefully, this new pool is in meters and not yards (right?); it tells you that you’re (finally) getting faster or that it’s been a while since you’ve been in the pool. But what if there was another way to help monitor and structure your workouts?

First, we’ll talk about a few useful metrics that triathletes should explore when they think about revamping the way they train in the water. Just like in running and biking, there are days when you need to focus on nothing more than time/distance/speed, but there are far more days when you need to leave time/distance/speed completely behind. Swimming should be the same. 

SWOLF, Strokes

While technique is something most triathletes already work on at the beginning of their swim workout, there’s also something to be said for working on efficiency during your main set. Efficiency is essential, particularly to triathletes, because unlike competitive pool swimmers (or competitive open-water swimmers), when we finish our swim in a race, there’s still way way more to go. Even if you have the fastest swim split in the field, it doesn’t mean anything at all if you get out of the water completely smashed and in a cardio/caloric deficit for your ride and run. One of the simplest ways to work on your efficiency is with the popular SWOLF score. A combination of “swim” and “golf” (which sounds extremely hard and dangerous on a first glance), you get your SWOLF score by combining your 50 or 100 time in seconds with the amount of strokes it took you to do it. In other words, if an athlete swims 42 seconds for 50 and takes 36 strokes, the SWOLF score would be 78. For more on this technique, check out our story on SWOLF, but we’ll share some devices below that help compute this score automatically. In a similar vein, you can also use stroke count as a metric in place of distance when swimming in the open water—which works even better if you already have a good understanding of your strokes per 50 or 100. 

Heart Rate

Swimming with heart rate is another tool in the efficiency box for triathletes. Much like when using the basic SWOLF score above, triathletes should be focusing on training that keeps their speed up with less effort—measured in this case via heart rate. In the past, heart-rate training in the pool was not ideal because of a few factors: First, for many reasons heart-rate monitors performed notoriously poorly in the water; second, even if you could get an accurate read on your heart rate in the pool (like the old finger on your pulse method) all it did was measure your recovery time. While this is valuable, for sure, it doesn’t necessarily help you become efficient from stroke to stroke. Eventually good heart-rate monitors came along that could at least collect the information reliably, but again, this was only useful for post-swim analysis, not real-time adjustments like in biking and running. 

The good news is that leaps in technology have solved those big problems with affordable and accurate heart-rate monitors that can either collect or transmit the data to a place where you can actually use it in real time—either in the pool, or better yet, in the open water, where metrics are sparse. In places without set distances, you can set your workouts in the open water just like you would for a bike ride or run, with specific zones for each interval and time. In the pool, you can take it a step further and work on finding that sweet spot between speed and efficiency by “playing” with your technique and pacing while trying not to drop time. We’ll talk about some devices you’d need below.


Cadence is a little bit different than the others in this list as it’s not necessarily a way to measure your effort, but it’s such an important metric in triathlon swimming that it bears mention. The ability to vary your cadence, even within a given effort/speed/distance is a key way to getting faster in the open water under different conditions and situations. While we won’t dive into cadence training, definitely take a look at this story about why it’s important and how to apply cadence. The TL;DR version says, you need to be able to work on a higher cadence for situations like starts, crowded swim sections, high waves, or strong head-on currents while knowing how to lower your rate efficiently for open sections of the swim or when currents are favorably behind you. While each swimmer has a different optimal swim cadence, we’ll share a device below that can help you lock that in and work on your range for the open water.


Now power probably seems like the most effective and efficient way to get better in swimming—like it does in cycling and to some extent running—but it’s also the most complicated in terms of logistics. While there are a few devices (one below) that can help, swimming with power isn’t nearly on the same level as cycling or even running with power yet (read here for more). Unless you’re using a dryland system, there’s no commercially available, practical way to monitor your swimming power while you’re actively swimming. And even if there was, the complexities of hydrodynamics and your swim stroke mean you’d probably only be getting like 60% of the picture, at best. That said, body position and kicking aside (which are not minor), knowing how much water you’re actually pulling is a good way to at least work on your stroke’s efficiency and can be a great benchmark for improving, even if it’s not something you can use in your daily workouts just yet.

The Swim Tracker Gear To Help You Break The Chains of Your Clock Overlord

Coros Pace 2

swim tracker

If you’re looking to use SWOLF, count strokes, or even distance/time in the open water, then you’ll need a GPS smartwatch like the Pace 2. There are more expensive options out there with SWOLF and open-water functions, but this watch is ideal because it is by far the tiniest and lightest smartwatch we’ve tested for swimming with the features a triathlete needs. And while you can change the data fields to display average SWOLF, stroke rate, distance per stroke, and way way more, the optical heart-rate feature on the Pace 2 isn’t amazing in the water, so you’ll want to read on for something more dedicated to that metric.

Polar OH1

Only recently has technology gotten to the place where tracking heart rate in the water works well. Polar’s OH1 is a favorite amongst swimmers (for a deeper review, check here) because you can put it on your arm or temple, and it not only stores your heart rate to download later if you want, but it now also broadcasts to smartwatches and some heads-up goggles (more below). The only downside to this unit is the rechargeable battery that needs to be topped up every few sessions, but of course nothing’s perfect.

FORM HUD Goggles

We’ve written extensively about these clever goggles that display useful information on the digital read out projected onto the lens, but they’re actually the key to many of the techniques we’ve spoken about here. With the sudden ability to track distance, time, stroke count, and heart rate in real time, these goggles open up a whole new way to work on your swim’s efficiency without being tied to a clock at all. However, you’ll need a heart-rate monitor like the one above and/or a compatible smartwatch like the Garmin Forerunner 955 or Apple Watch to get heart-rate and open-water metrics, respectively. That said, even with the built-in metrics that these goggles can produce, you can pretty much eliminate a pool clock entirely, as it’ll tell you everything you need to know about your split, your recovery time, and way more. It’ll even interpret your swim and spit out a handy log of your sets post workout or let you load premade workouts in before you begin.

Finis Tempo Trainer Pro

This handy little device will fit beneath your swim cap and make a little audible tone at whatever rate you set it. This is a great way to not only work on maintaining your optimal cadence while swimming long sets, but also helps ensure you’re training a range of cadences for different tri swimming situations. 

Vasa Swimerg (with power meter)
Starting at $2,300,

The only true foolproof way to train your swim with realtime power right now is on dry land. The Vasa Swimerg is not even remotely cheap, but it’ll output your stroke power to a display or training service to give you a sense of exactly how much effort your arms are putting out in the swim.

Video: 4X World Champion Mirinda Carfrae Makes Her Picks for 70.3 Chattanooga

Carfrae and former pro Patrick Mckeon break down the iconic course in Chattanooga, who looks good for the pro women's race, and their predictions for how the day will play out.