All analysis of workouts are based on reported workouts done by the athletes. There are several different graphs regarding workouts displaying different perspectives: Training Load (default), Exertion, Category, No of Workouts and Time of day for workouts. You can easily change perspective in the upper right corner of the graph.
Graph Training Load
Training Load is based on (Session RPE x Time) / 2. Each workout are planned and reported on Session RPE and Workout time giving a measure about how hard the Workout was for the athlete.
Graph No of Workouts
Graph Time of day