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Building your swim threshold

There is a lot to think about with swimming; the technique, the breathing and then how hard to push without losing that technique.

Swimming is a balancing act. If you are forcing every bit of energy out of yourself, you are bound to be just “thrashing through the water” and not moving forward the way you wanted to. Bringing your effort back ever so slightly, and holding better technique and posture is where you excel.

First things first when starting off swimming / triathlon– Get your technique right! Loads of coaches out there are selling to touch up your technique before you go digging into 4 x 1000m @ race pace!

What is threshold?

Threshold sets are an effort level between aerobic and anaerobic, or in other words where lactate does not accumulate significantly. I would call this about 80% effort. We look at this effort for what you could potentially hold for 800m.

So how do we get our threshold times?

For beginners swimming can often be one effort level – HARD. Absolutely understandable, and that is why a bit of technique coaching is recommended first, then build into it.

As we all want to see improvements, at Evolve Triathlon Coaching we usually do “Fitness testing” every 6-8 weeks to see how you are tracking.

To get your threshold times we will get you to da a 400m timed and a 200m timed. We then use a critical speed calculator from

Now onto the important question of “How can we improve our threshold swimming?”

We want to make sure that we balance endurance and threshold swimming. Don’t just go for a swim. You need to work on slower/longer work (endurance), and then moderate harder work (threshold), and finally FAST short work (speed).

In my experience, after being a competitive swimmer for 5 years and then a professional triathlete for 13 years, you need to swim a bare minimum of 2 x a week, 3 is good , 4 would be ideal, to see improvements. However, I understand most people have some time restraints and may not be able to swim four times per week.

Here I have 3 key threshold sets we do in our squad that will help boost that fitness!

Session 1)

W.U – 500 S.P.I.K.S (Swim / Pull / I.M / Kick / Swim)

4 x 25 drills of your choice

4 x 75 as breathing 3/5/7 - Rest 20”

4 x 50 build to 90% Rest 20”

M.S – 8 x 100 @ threshold pace – Rest 20” (Intermediate do 10, advanced do 12)

C.D – 300 Pull steady

200 easy mixed

Session 2)

W.U: 100 swim, 50 drill (your choice), 100 swim, 50 drill. M.S: All at Your Lactate Threshold pace 350 @ Threshold Pace – Then straight into- 50 easy. - R.I 10" 300 @ Threshold Pace 50 east. R.I 10" 250 @ Threshold Pace 50 easy. R.I 10" 200 @ Threshold Pace 50 easy. - R.I 10" 150 @ Threshold Pace 50 easy.

C.D 200 Mixed

Session 3)

W.U: 6 x 100 as odds 75 free/25 back, evens with Fins steady - R.I 20" 4 x 50 builds to 90% - R.I 15" 4 x 400 @ All at Your Lactate Threshold pace ,try to keep these as even as possible!

C.D 100 backstroke 200 Kick easy with board 200 Pull buoy only Z2

Build into this over time. Do 6 x 100m @ threshold, then next week 8, then 10. Then move into 200s, then finally 4 x 400’s @threshold pace.

Happy training!


Hi Tony. Interesting article, thank you for writing and posting:) Could you please clarify what the abbreviations stand for in plans? Thanks. Julia, Complete Beginner

Tony Dodds
Tony Dodds
Aug 05, 2021
Replying to

Hi Julia, ahh yes sorry I did forget that!

So " means seconds

' means minutes

R.I - is rest interval

W.U - Warm up

M.S - Main set

C.D- Cool Down

Z2 - Is Zone 2 (or steady swimming at around 60% effort)

I hope that helps :)

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