Adaptive training workout number (or grades ?)

[tkoberle]

I just noticed that, as part of the predictive training update, workouts now come with a number (grade) next to the workout name. Tomorrow I am on a “Sweet Spot 6.9” w/o.
What does that number mean ?

[mcneese.chad]

Introducing Workout Levels: A New Way to Understand A Workout's Difficulty -...

Also info in the FAQ further down in this announcement.

New Product Release! Updated Training Plans, Workout Levels, TrainNow Updates

When we announced Adaptive Training, we promised to roll out individual pieces once we felt they were ready, instead of doing a single big release of everything down the road. Today, we’re excited to release three significant new features from Adaptive Training to every TrainerRoad athlete! Updated Training Plans We’ve updated all 100 of our training plans using insights from our machine learning to improve the sustainability of progressions & ramp rates. In all, these insights resulted in ov…