Lucy Charles-Barclay won the Ironman World Championships in October 2023, leading from the front throughout the race.

Lucy stayed at home in London before the race and almost exclusively trained indoors on Zwift to prepare for the event.

A Level 60 Zwifter, this is one of her favorite sessions. The interval session includes 5 reps of 3 minutes at Upper Aerobic Threshold, 1 minute right at FTP and then 1 minute rest.

This session should be uncomfortable but achievable and is a good one to do on a regular basis.