1600m at mod pace w/ 4min rest
200m sprint w/ 2min rest
1200m at mod/fast pace w/ 3min rest
4x100m sprints w/ 1min rest,
800m at mod pace.
Workout Details: Run 1600, rest 4min, sprint 200m, rest 2min, run 1200m, rest 3min, sprint 100m at max effort, rest 1min, sprint 100m at max effort, rest 1min, sprint 100m at max effort, rest 1min, sprint 100m at max effort, rest 1min, run 800m.
Workout Pacing: The opening 1600m interval should feel sustainable. You closing 800m interval must be at the same pace as your opening 1600m interval. This might prove challenging because of your accumulated muscular fatigue.
Workout Focus: The 4x100m sprints are programmed to be sprints. Your accumulated time for these 4x100s must be faster than your current 400m PR time. Attack this set from the beginning and never let up on the gas pedal.