17/20s: A Simple but Powerful Swim Set to Unlock Free Speed
by Paul Eaglestone
If you’re struggling to improve your swim speed despite spending hours a week in the pool, consider incorporating my signature 17/20 set into your programme. This is a simple but powerful tool to systemically build your ability to maintain a target pace for longer and longer distances.
I have used this set for many years with athletes ranging from a young Alex Yee – the 2024 Olympic triathlon champion – to frustrated age-groupers searching for a breakthrough later in life. It teaches you to hold form and technique at higher intensities and improve efficiency and pace at any given effort.
The details of this are featured in my book Free Speed, but the concept is straightforward: you are aiming to be able to swim 25-metre lengths in 17 strokes (or less) in a time of 20 seconds or less.
This is based on the work I did with elite junior and higher-level amateur athletes and won’t be achievable for everyone, but it is totally scalable for anyone by working out a baseline and setting personal targets. The aim is to swim 16 repeats off a short recovery. When and if you can achieve 17/20, you are training at an excellent level of efficiency and pace.
If you think 17/20 is impossible based on your present swimming level… that’s exactly why you need the set. 17/20 is the destination, not the starting point: we start with four or six reps in whatever you can do – this might be 20-25 strokes per length, in 25-30 seconds each. It doesn’t matter: the point is to gradually reduce stroke count and increase pace towards the 17/20 goal and then increase the number of reps.
In doing this you need to pay close attention to your form to increase distance per stroke and increase your top-end speed. Once you can do this, try to reduce your effort level at the same pace, cadence and distance per stroke, and you will find your cruising pace will increase in turn.
One of my athletes is Daniel Bentley, a GB age-grouper who came to triathlon in his 40s without much swim background. While he has a big aerobic engine from decades of long-distance running and now cycling, his swimming has been holding him back by his own admission.
Too much focus on slow, endurance swimming and drills had left him with little top-end speed and a stroke that fell apart under intensity. I suggested he incorporate 17/20s into his programme and he could see positive adaptations within weeks.
Daniel said:
“Having done lots of swim training focused on endurance and lower-intensity work, Paul has demonstrated to me the importance of training to hold form at higher-intensities for progressively longer distances.
“This is what the 17/20 set provides – a time-efficient and intuitive way to benchmark your pace and then steadily build your neuromuscular capacity to hold target pace. I have now incorporated this into every session and can see my pace picking up across the board.”
Once you can do 16x17/20s (including if you are at an elite level, and already can do so), you can then extend the same principles and either reduce the stroke count and time further to 15/15s or even move onto repetitions of 50 and 100 metres.
17/20s are not a shortcut or a cheat code to becoming a faster swimmer, which takes a lot of hard work, consistency and commitment over a long period of time. Done right, these sets are hard – and they should be. But teaching your body to hold form at higher intensities is an essential part of the process – and 17/20s provide a structured approach to doing this, unlocking faster paces at all intensities and helping you achieve your potential in the water.
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Paul Eaglestone swam competitively from childhood to his early twenties, including with a national squad. He has coached swimming and triathlon for 30 years, and he is still taking athletes to the podium today. Paul was Alex Yee’s swim coach throughout Yee’s teens. Athletes use Paul’s methods in coached sessions as well as in their own self-directed training. The Covid-19 lockdown was Paul’s opportunity to commit the method he had developed over the course of his career into the pages of a book, Free Speed. He is passionate about spreading his training ideas, which are simple but highly effective, to as many people as possible, particularly those who may not have their own coaches.