
Two years ago there was a 400 runner who did distance workouts from 400 up to two miles. He never ran under 50 seconds. Last year I took over sprints and he never ran over 600 meters in a workout but did lactic acid tolerance workouts along with speed training. He placed second in the state convincingly over third. He ran a personal best of 48.5 fully automatic. He could also run a 10.8 and 22.4 hand times. My two hundred meter runner never ran over 400 meters at a time. I believe if you train them like a distance runner they will run like one.
I do not want my 400 meter sprinters meddled with by 800 mechanics. There is so much to consider about how their race is run and how speed plays a strong role in the float phase and transition phases of the race.