Want to blast the 40km bike leg? Then follow this essential set for improving your surges in speed, passing power and lactate threshold.
It’s a tough session, but doesn’t take a long time to recover from because, although intense, it’s relatively short.
Equipment needed: ideally a tri bike, but this can be done on a road bike or the turbo trainer. I like doing it on a steady climb. Know your lactate threshold before you start.



15mins as: 12min spin, working your way up to 100-110% of lactate threshold (LT); 3mins easy spin


Main session

30mins as: 6 x [40secs @ 120% LT/20secs easy spin]; 4mins @ 100% LT; 10mins recovery then repeat once, straight into…



15mins easy spin.
Here is the session available to download for use in Zwift


Performance benefits

This workout is best done on a TT bike with your goal being to complete all of the 40sec efforts and the 4min LT effort on the aerobars. It will help create the ability to change speeds and surge during races without emptying the tank.


Mental benefits

This is a tough session. As you’re getting to the last couple of 40sec efforts on the second set you should be feeling it in your legs.
Having the ability to take your 20sec easy – and then go right into a 4min effort at threshold – will give you confidence during a race to hold your pace once the legs tire.


Physiological benefits

This set will increase your lactic threshold power, ability to ride at a concerted effort for an hour and your overall stamina. It’ll also help you control and be aware of your changes in heart rate.


Adapt for Ironman

I’d increase the number of reps to 8 or 10 in each set, and I’d make the lactate threshold effort 8-10mins and drop the effort to 90-95%. Over time you could also add in a third set.

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About the Author: Kyran