Favorite Workout: Threshold 400s

by GRP runner Andrew Tario

End-of-season breaks are important for rejuvenation, both physically and mentally. However, getting back into shape can be very daunting as your next race goal looms. One way to get over the fear or anxiety associated with getting back into structured running workouts is to break hard efforts up into short repetitions. This makes the workout more digestible mentally, while still delivering great physical benefits. One way to do this is by doing threshold 400s.

“Threshold” isn’t a new word in endurance training, but it does seem to be a buzzword that is getting thrown around a lot more than usual lately. I don’t claim to be a scientist, but I do know how to look things up on Google, and simply put by famed distance running coach Jack Daniels, the purpose of threshold training is “to stress lactate-clearance capability, not to overstress that capability.” I prefer to think of it as “hard, but not too hard.” If your legs feel like they’re building up lactic acid exponentially as the workout progresses, you may be working harder than true threshold pace.

An easy introduction to threshold training is to run threshold 400s, or quarter mile repetitions. These can be done on a track (one lap in lane one on a standard outdoor track) or on a measured course on roads. An example of this workout would be 12 reps of 400 meters, with a short 35 second rest. By only running 400 meters, you are able to run faster than if you were doing longer repetitions, like miles, but the short rest allows you to catch your breath and let that lactate level dip a bit before starting the next repetition. However, if you aren’t used to doing this type of workout, the short rest may come as a shock at first! You can certainly start with longer rest (such as 2 minutes), and progress to shorter rest over the course of a few weeks’ worth of workouts. But if you decide to do longer rest, make sure you are still running the workout at threshold pace.

Ideally, you’ll want to finish this workout feeling like you worked hard, but could do 3 or 4 more repetitions if you have to. The point is not to push yourself as hard as you can; the goal is to work in that “comfortably hard” zone without going over the edge. If you’re looking for a new workout to add to your arsenal, threshold 400s are a great way to begin!

Jack Daniels’ article on threshold training