Yeah, this graphic is at first not really straightforward to understand and apart from all the other stuff I feel this one is not yet optimally explained.
But once understood it does make sense - at least for me.
So as @bbarrera already contributed to this thread, all the columns are basically the least and maximum times of optimal training stress for the respective athlete based on his VO2max and therefore potential protein synthesis capability. Also lactate clearing capability, available glycogen and a few other parameters are considered.
So then each column for each training zone or training target shows the weekly min max times.
That means: if you are doing only base training in one week, you would be best served with at least the light blue column and max the darker blue column.
For each other target zone the red columns are the intensity times and the blue columns are the low intensity times. So depending from his parameters the Sprinter Athlete 1 should do (when in a VO2max block) maximal 1:06 hours in VO2max range and then still had to ride another 8:42 h in base range (either in separate workouts as well as in part as Time in zone in the VO2 workouts of that week).