5,4,3,2,1 Pyramid

We did this one in college often and it was always one of my favorites.  I like it because it enables you to use a variety of different speeds and distances.  By having the combination of longer and shorter intervals you are really able to delve into your lactate threshold as you have a shorter recovery than what you just pushed yourself to do.

Warm up: 10-20 minutes depending on what you need

Main Set
5 minutes RPE 10 (or race pace)
4 minute recovery
4 minutes RPE 10
3 minutes recovery
3 minutes RPE 10
2 minutes recovery
2 minute RPE 10
1 minute recovery
1 minute RPE 10

Cool down 10-15 minutes

The other cool thing about this workout is that you can turn around and go back up; 1,2,3,4,5 in order to make it a longer workout.