I did a 400m simulation workout where I ran the first 150, second 150, and final 100. The rest was walk back a 50 and build into the next interval. I did the workout twice. Splits were 15.5, 17.3, and 11.3 on one workout and 16.5, 17, and 10.1 on another. How fast could I likely run a fool 400? Hopefully fast since the workouts add up to 44.7 and 43.6