L'Etape du Tour will require a largely aerobic effort from you. With 135km and 4563m in elevation gain, the more efficient you are in your fuel source, the more energy you will have for the final climb to the finish.
Aerobic Endurance workouts are aimed at improving your efficiency at lower intensity levels. Training your muscles to access fat as its main fuel source and preserve your precious glycogen stores for the finale.
After warming up, you will be completing 3 x 12min aerobic efforts with 3min recovery.