6x400m w/400m jog rest ... Start at about 2-3s/lap slower than current mile pace and cut down 3s/rep. Goal for this group was 69/66/63/60/57/54. Lap jog rest takes 2-3min.

Many great teaching points in this workout. This workout is used by me as a "transition" workout from our heavier aerobic work into our more anaerobic work. (Lets me know if they're ready for it!) It gives me a good idea of how fast they can run while tired more than anything. There isn't a ton of lactic acid/byproducts produced during this workout until the last couple reps anyway, so there generally isn't much locking up. Timing the rest time is also a good way to get a feel for how well their aerobic system is doing; if they're struggling too much to keep under 3min on the rest -- especially for the first 3-4 reps -- then they're probably in need of a lot more aerobic work. And as can be the case with many workouts, if somebody gets "lazy" on #4/5 because it's starting to get a little tough, but then they still come back with their fastest on #6, it's a great teaching point to let them know that just because they think they felt tired they actually weren't.