From what we saw in that other thread, Brenda Martinez's "base training" months ago included such workouts as 4 miles in 20:22. Surely she could do that same workout in 20:00 now. And if she can run 4 miles at a 5:00 as a workout, how could she not run 3.1 miles at 4:50 in a race? She's got to be in sub-15 shape.