Sports Illustrated:
" One of Handler’s favorite short workouts for Berian is a series of five 150-meter sprints in 15-16 seconds, which is the type of training that a 200-meter specialist might do. One of their favorite longer sessions is 3X400 meters in successive times of 48, 47 and 46 seconds, each faster than the one before, with 10 minutes’ rest between sessions".
An example of the training that I´ve been talking about, which seems to be often neglected. You can´t have a good anaerobic power (fast 400´s) without a good basic speed and anaerobic capacity (the ~150m sprints). But like also said you can´t use the speed, if both the anaerobic and the aerobic capacity isn´t in balance for the event.