Training paces in this lab come from Jack Daniels’ VDOT system. A recent race distance and time estimate VDOT, an index of current endurance fitness. That value is converted to velocities at percentages of VO2 for recovery, easy, tempo, threshold, and interval running.
The bands are training estimates, not prescriptions. They assume the race you entered is representative of current fitness. They do not replace coaching, and they do not know your injury history, terrain, or how many sessions you can recover from this week.
If you want the exact pace for a target race rather than training zones, use a race-distance calculator. If you train by heart rate, open the heart-rate zone calculator. Cite: Daniels’ Running Formula. Details and limits are on the methodology page.