This is a race-readiness session, not a fitness test. Twelve times over, Juliette holds ninety seconds at VO2 max and then sprints flat out for thirty seconds, so the decisive effort always arrives on top of sustained pressure. That order is the whole point: in a race the sprint is never taken fresh.

The session is built in two sets of six so the second set is ridden on real fatigue, with fifteen minutes between them to let W′ recover enough that the sprints stay honest. The five-minute recoveries inside each set are long on purpose. Short recoveries would turn this into a lactate session; these keep every ninety-second effort near maximal oxygen uptake and every sprint near peak power.

In Vekta the ninety-second efforts are written at 105–130% of CP and the sprints at 180–500%, so the session scales to any rider's numbers rather than to Juliette's watts. The W′ preview shows the drain across the twelve repeats before you ride it, and the analysis afterwards names each effort and tells you whether the sprints held up in the second set.

Use it in the last block before a target race, once a week at most, on a day when you are fresh enough to sprint properly. If the sprints fade badly in set two, the VO2 efforts were too hard, not the sprints.