WILT Intervals

Ventoux 100 minutes at Threshold
(in my UCI Golden Bike Jersey)

When & Why?
The WILT intervals (Williams'; Intensity Level Threshold) are aptly named because WILT is the acronym that describes the interval and wilted is what you will be at the end. 

In the first minutes you'll be wondering what it's all about, at the end you'll be begging for the finish.  In between you'll get bored, hot and your legs will hurt.  It's death by a thousand cuts, but boy does it work.  I'm using them exclusively for my 24 hour Ventoux Masters event.  For an added challenge, try doing them twice a day!

This deceptively challenging block of intervals can be used in the pre-competition phase or anytime in the mid-season to give a boost to your hill climbing, time trialling, or just plain ability to suffer on a lone breakaway.

You won't like it but once again, it brings results.  And if it was easy, everyone would be doing them.

Try it once a week in a four week build up to a 25 mile or 50 mile TT.  Or use it in the early season to build FTP endurance.  You can even do a session once a week throughout the season, if you have the mental fortitude and physical constitution. 

It's especially good for those day's when it's raining outside and you need a good workout.

You don't absolutely need power to do this interval, it can be adapted, please see the end of the page.

Really only suited to a turbo, which will become obvious once you've done one! 

Find your Functional Threshold Power then add a 10 or 20 watts premium.  Say you have 250 watts FTP; add a 20 watts premium and you get a 270 watts interval target.

Start by getting to your FTP + premium wattage as soon as you can within the interval but without "sprinting to it".  No shocks to the system, just a concentrated increase in wattage from recovery to effort in one long linear fashion.

Once the warm up is over; start with one minute at your target wattage.  Take a one minute recovery.

Then move to two minutes at target then another minute recovery.  At his point you'll be wondering what all the fuss is about and "When's it going to start?"  Patience, my little champions, patience.

Four minutes, comes next (have you worked it out yet?) followed by a one minute recovery.  In to eight minutes on, one minute off, then sixteen minutes on.  Now, we've got your attention!

At the end of sixteen minutes you will be very hot, very bothered and on the verge of wilting.  You now have one minute to recover before you head in to the "thirty-two minute tunnel of darkness."

You may not come out the other end.  At some point you will either die of boredom, heat exhaustion, drown in your own sweat or just plain run out of puff.  When you do, make a note of the time.  That's what you need to beat next time.

On the glorious day that you do get to the end, (after treating yourself to a Chinese and a Vienetta (that's food by the way!)) you can ramp up the wattage another ten watts and enjoy the experience all over again.  Feel free to email me with your thoughts...

The Warm Up Warning
All interval sessions require a thorough and proper warm up...

Once thoroughly warmed up and at "race pace" readiness, undertake the following session.

Session Description

One minute on  
One minute recovery  
Two minutes on  
One minute recovery  
Four minutes on  
One minute recovery  
Eight minutes on  
One minute recovery  
Sixteen minutes on  
One minute recovery  
Up to Thirty-Two minutes on  
Cool Down    

Session Timings

Warm Up 10  
Interval Effort 63  
Interval Recovery 5  
Cool Down 5  
Total Session Time 83 mins max

Session Schematic


  Duration in minutes shown up the side ~ not to scale

Obviously this is a long session if you manage to get to the end.  But you should only get to the end once!  Because when you do, you start again, with increased wattage targets. 

Most session times will be 60-70 minutes.  Just taking the session to 16 minutes, still gives 31 minutes of Threshold effort.  If you're stuck for time or just need a "top-up" you can stop the session at the end of sixteen minutes.

If you don't have a power meter, or a power based turbo, just adapt your session to kilometres or miles an hour until you find you can only get around 10 minutes in to the 32 minute interval.  Heart rate isn't really appropriate as you get cardiac drift and the early intervals can't be paced by heart rate.

Here's a WKO+ screenshot of a session...

Flamme Rouge WILT Interval