🔷 "Swimming by Numbers"

The What, Why & How of Optimising Your Training Time in the Pool & Open Water

TL;DR (In summary - as today’s blog is very comprehensive!):

When it comes to improving your swimming, some love crunching the numbers, while others prefer to swim by feel. The good news? You don’t have to choose between the two! A smart blend of structure and intuition can help you train more effectively while keeping the joy in your swimming.

1️⃣ Why It Matters – Basing your ‘swimming by numbers’ off one simple number—like CSS pace—gives you a clear, objective measure to work with, rather than the vague idea of "swim at 70% effort," which can feel different from day to day and be much harder to track long-term. That said, there's a time and place for both—swimming by numbers for precision, and swimming by feel to stay in tune with the water and develop your innate sense of pacing. We’ll look at how to gamify both.

2️⃣ Your Training Toolkit – From simple pool clocks and stopwatches to smartwatches and the Finis Tempo Trainer PRO, each tool has its pros and cons, all of which we’ll examine. The trusty Tempo Trainer is still a real game-changer—plus, we’ve got an exclusive 25% discount for you!

3️⃣ FREE Training Peaks Webinar – If you want to dive deeper into training with data, join our Training Peaks webinar next week to learn how to optimize your swim training!

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Hey Swimmers,

Before we get stuck into this week’s blog, I’m very pleased to announce that next Wednesday, 12th February, at 4pm MST (11pm UTC and 10am AEST on Thursday 13th February), I’ve been invited to be a host speaker for the world’s largest endurance training platform, Training Peaks, to deliver a FREE webinar on swimming for triathlon:

I’ll be joined by my good friend and co-host, Dr Dan Plews from Endure IQ, who has produced 30 World & Olympic medallists, as well as had 16 Pro Ironman & 70.3 winners, and whom has published 58 scientific papers on everything to do with endurance training - he’s a bit of a legend and someone I’m very proud to call a mate!

The webinar will be recorded, but since there will be a Q&A session, we’d love to have you join us live if possible!

Now, about that title 👆(before anyone gets offended!) - Training Peaks - the host platform - is of course primarily geared towards the triathlon market, however, in place of the word “Triathletes” you could easily insert “Open Water Swimmers” or “Distance Swimmers” or really anyone who swims long-distance freestyle and wants to know more about how to improve their Technique, Training & Open Water Skills.

You see, the internet is still full of swimming tips on what people ‘believe’ to be classically efficient and techniques primarily focused on sprint events and all four strokes—which is perfectly fine. However, that’s never been our focus. We’ve always been about helping you find the best stroke technique for you as an individual and for the discipline/environment you’re most keen on, no matter what it looks like:

“People say I have quite a messy stroke and that I don’t kick…but it seems to have served me well, especially in the open water and for triathlon!”

Lucy Charles-Barclay, 2023 Ironman World Champion

So, if that advice and sentiment worked for Lucy (see video and our exclusive interview discussing it here¹) as well as 3 other female Ironman World Champions (watch full video here²), then there’s a good chance it will work well for you too!

Recognising this, Training Peaks invited us to share our expertise, ensuring that the swim training advice you follow is not only highly specific but also measurable and actionable—especially crucial for those training remotely.

Swim Smooth X Endure IQ X Training Peaks

This is also why Dr. Dan Plews approached us to collaborate on an exciting project—bringing the Swim Smooth GURU’s extensive library of highly specific swim sessions exclusively to his Endure IQ Squad and our Certified Swim Smooth Coaches within Training Peaks. For triathletes, having Dan and his expert coaching team design your full triathlon plan, backed by the precision and effectiveness of the Swim Smooth GURU, is a game-changer. You can find out more about the Endure IQ Squad here and get 50% off your first month with them.

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🔷 Today’s BLOG: "Swimming by Numbers"

The What, Why & How of Optimising Your Training Time in the Pool & Open Water

The webinar with Training Peaks next week feels like somewhat of a “full circle”.

Back in January 2007 I flew down to Colorado Springs to meet with the Training Peaks team as part of their annual “Technology Convention”. I’d just bought the book “Training & Racing With Power” by Hunter Allan and Dr Andy Coggan and was both inspired by it’s teachings and simplified approach to cycling with a power meter, as well as enthused to meet the team behind all the tech. I also came prepared with a formula I’d been working on to calculate sTSS (Swim Training Stress Score - still in use today), to ‘complete’ the trifecta with bike and run.

The fundamental takeaway from that book was that in the absence of expensive laboratory testing, one could measure their threshold power with a very simple test on their bike and then use this absolute number (Functional Threshold Power or ‘FTP’) to create training zones relative to this specific number.

I wanted to utilise something like this for swimming, as it eliminated the guesswork from training. Instead of relying on the highly variable measure of heart rate—widely popularized in the ’90s—or the subjective instruction to “ride at 70% perceived exertion,” both of which often lead to suboptimal training outcomes, athletes could follow fundamental sports science principles. By accurately measuring training load and making informed, data-driven adjustments, they could ensure continuous progression and optimal adaptation.

Now, if that all sounds overly clinical, robotic and potentially anxiety provoking—far removed from the freedom and escape that draws so many to swimming—consider this: applying these same principles to your swim training can be as simple as "swimming by numbers." By understanding key metrics like your CSS pace (Critical Swim Speed), how to test it, how to pace yourself correctly, how to record your efforts and then how to make small, targeted adjustments, you can strike the perfect balance between structure and feel.

And, with a little Swim Smooth Magic, we can gamify that whole process so that it’s not just effective, but a lot of fun too!

Here’s how to get it right—and what to avoid!

The PROs and CONs of How to “Swim by Numbers”

OK, so we’ve spoken ad nauseam over the the years about:

• the importance of knowing your CSS pace,

• how to test for it,

• shown you some of the weird results you might have come across,

• provided a basic guide for those totally new to the concept,

• discussed the difference between some of our more advanced concepts like CSS Paces and Red Mist Cycles,

• and have even provided you with a way to calculate all the good stuff that comes from knowing this one simple number, like your physiological profile and time predictions over different distances (uncannily accurate we have to say!)

So, I’m not going to rehash all of that today. Goodness knows, you’ve probably got better things to be doing! Instead, we’re going to look at the different tools that many of you use to measure your “swimming by numbers” and the PROs and CONs of each. We’ll then round out with a few sage tips for those of you who’ve ever experienced any anxiety whilst trying to swim in this objective manner to a set pace, especially when part of a squad.

To start, please watch this 4-min video with one of my swimmers this week where we lay out the foundational principles of the drawbacks and ambiguity of using perceived exertion for your intervals, why smart devices are usually only good for retrospective feedback, and how and why the trusty Finis Tempo Trainer PRO still packs a punch even after all these years:

Which Device Should You Use?

1. The Pool Clock ⭐️

PROs - simple enough to read and usually always available | no cost to you | fine if you’ve grown up with such vernacular as “red on the top!”, a mystery if you haven’t!
CONs - not that accurate (“did I finish on the 7 or 9?”) | hard to calculate cycle times when using odd numbers to be more precise | easy to “cheat” | hard to read for the eyesight poor | feedback is only ever retrospective | no recorded data

2. The Coach’s Stopwatch ⭐️⭐️

PROs - you don’t have to do anything (leave it to the coach!) | only cost is the coaching | may get pacing splits from a very good coach
CONs - the coach will struggle to get everyone’s times in a busy session | accuracy of data sometimes questionable | limited record of your data

3. Smart Watches ⭐️⭐️⭐️⭐️

PROs - record of your data for each swim | some real-time feedback of total interval time/pace within a set | can follow a session on the device | our recommended devices: Garmin 965 & Apple Watch SE.
CONs - cost | accuracy of data (albeit improving!) | pacing feedback within an interval limited | can be distracting (more so for the coach seeing you fiddling with your buttons!)

4. Other Smart Devices ⭐️⭐️⭐️

PROs - record of your data for each swim | some real-time feedback as you swim (on pace and technique) | can follow a session on the device | accuracy of data
CONs - cost | can be distracting and ‘alienating’ within a squad session especially | through-vision and wider field of view ‘not quite there’ yet | some report in-your-face ‘information overload’ akin to running on a treadmill and always being aware of your time

5. Finis Tempo Trainer PRO ⭐️⭐️⭐️⭐️⭐️

PROs - simple to set up and use | accurate to 1/100th of a second | enhances the gamification of your sessions | keeps the concern about specificity of your target times, your pacing, and your accountability to a minimum - either stick with the beeper on a CSS set, or beat it on a Red Mist Cycle: simples!
CONs - no record of your data (though, if you know you’ve hit your targets and are also using a smart device for the recording, who cares?) | some struggle to hear the beep | cost*

Gamifying Your Swims

So, now you’ve taken a look at which devices will serve you best in the pool (our pick being the Finis Tempo Trainer PRO to set your targets accurately and then a smartwatch to record that data to analyse and provide actionable insight in the Swim Smooth GURU), how about some practical session ideas utilising the Finis Tempo Trainer PRO to really gamify your “swimming by numbers” experience:

Striking the Balance Between Swimming by Numbers and Swimming by Feel

At the heart of “Swimming by Numbers” is the idea that structure and data don’t have to take away from the joy of swimming—they can actually enhance it. Whether you’re using a Tempo Trainer, a smartwatch, or the humble pool clock, the goal is the same: to train smarter, pace yourself better, and unlock consistency in your swimming.

But remember, while numbers provide clarity and progression, they shouldn’t dictate your entire experience. The real magic happens when you blend data with feel, allowing objective feedback to refine your pacing, while still embracing the rhythm and flow of the water.

If you’ve ever struggled with pacing anxiety, over-reliance on devices, or feeling “trapped” by numbers, you’re not alone. The key is finding the right balance—leveraging the tools that work best for you without losing the sense of freedom that makes swimming so rewarding.

Oftentimes, this anxiety is felt most when leading a lane or group in your lane and the coach has asked you to hold a set pace or “stick with the beeper!”. However, there’s no need to feel anxiety - if you’ve stepped up to the plate (and no one else has) - then everyone else has to be accepting of that fact. So, win, lose, or draw with the target - just do your best and use it as a simple yard stick. It’s not the end of the world if you don’t make it! Having the confidence to take the lead like this and dial into your pacing at a speed specific for you, is where you’ll always make your biggest gains. It’s why I always say you’re better off leading a lane ‘down’, than hanging onto the back of a lane ‘up’.

Next week’s Training Peaks webinar will explore this concept even further, diving into how to optimize your swim training using data while keeping it fun and engaging. If you’re ready to fine-tune your approach and take the guesswork out of your swim sessions, make sure to join us.

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*since the pandemic, the availability of the Finis Tempo Trainer PRO has been limited, and prices have increased. While we haven’t stocked them for several years, we’re pleased to offer you a 25% discount when ordering directly—just use the code swimsmooth at checkout on the EU website or US website.

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