From the BarryS Coaching Training Library

Predict your IRONMAN Swim Time

by Mike Jotautus

Last week I worked with an athlete who had an I'd be happy if… goal of completing the IRONMAN swim in 1:45.

It would mark a 20-minute improvement on his previous IRONMAN swim from several years ago.

He told me that during his long training swims this season he had been averaging ~2m30s per 100m (he was being very conservative).

I predicted that with the help of his wetsuit and the downstream current he should anticipate a 1h35min swim.

His swim time was 1h32mins at IRONMAN Louisville this past weekend.

If your training has been consistent it shouldn't be rocket science to predict performance.

Here's a 3800m (2.4mi) swim set that you could use to get a good idea of your current IRON-distance swim time.

Take a look at the workout, watch this brief explanation, then read on.

red mist workout

How to predict the length of time it will take you to complete this 3800m swim set:

Multiply your CSS pace per 100m by 38. This will give you the time it would take you to swim 3800m if you swam it all at your CSS pace.

...I know what you’re thinking. It's impossible to swim an iron-distance swim AT your lactate threshold pace.

...and, you are 100% correct!

Notice the cycle time for all the intervals is RM 5.

This simply means your Tempo Trainer Pro is set at an interval :10sec per 100m slower than your CSS pace. Add that up over 3800m and you get 6m20sec.

Add 6min20sec to your estimated time above and you have the length of time it will take to complete this workout.

As you start swimming through the set, the goal is simply to beat the beeper and stay ahead of it.

At the end of each interval, the amount of time ahead of the beeper you earn becomes the amount rest you get.

If your current CSS pace is 2:13/100m you would complete this whole workout in 90minutes and 30 seconds!

How cool is that?!?

So there you have it, a good measure of how you’d fare on your IRON-distance swim. A 3800m workout with rest intervals (albeit very short) in 90minutes!

Let me know how this one goes for you! 


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