With all coaches there is always that one workout that is the make or break type workout. When I was training with team USA Minnesota, that workout was 3 mile by 2 mile by 2 mile by 1 mile with 5 minute recovery. The paces start out at 10 seconds faster than marathon pace for the first 3 miles, the 2 mile intervals are done at 10k pace, and the last 1 mile is done as fast as you can run. When this was on the schedule, there was always an extra level of trepidation that came along with doing this workout. If the workout went well I knew the upcoming season of racing would go well, but if it didnÍt then there was some more work that needed to be done.
This workout is a great workout to do as it simulates a race type effort, and forces you to get use to changing pace. Anyone who has experience running road races knows there can be a lot of surges within the race. This workout simulates that by having you change paces. By running the last mile as fast as you can, this imitates the kick that comes at the end of the race.
Since I have started coaching, I still use this workout with my athletes. Depending on their ability level and the distance for which they are training, there are some modifications that I make to this workout. Instead of using distance for the intervals, I have changed it to time using the 15-10-10-5 with 5 minutes of recovery. The paces are still done at the same goal paces for all athletes. Depending on the level of the athlete that I am working with, sometimes I will drop one of the 10 minute intervals to decrease the intensity of the workout.
This is a great workout to do about 4-6 weeks out from your goal race for the season. If you are new to long threshold workouts, I would recommend starting with one less 10 minute interval during the workout.