Workout of the Day: 3 x (6 x 400m)
3 x (6 x 400m)
Intensity — 3K pace
Recovery — 100m float after each rep, 3 - 4 minutes walk/jog between sets
Exertion — 9/10
Context & Details
This workout is the gold standard of short-endurance (3K - 10K) fitness. I think it should be a staple workout in every short-endurance runner’s program.
Why?
It upgrades three critical performance variables concurrently: vVO2 Max, Lactate-Threshold Velocity, and running economy.
Think of this workout like 3 x 3,000m, but with 100m semi-easy floats after every 400m. I like to keep a record of the 400m rep times, 100m float times, and overall 3,000m time. A jump in fitness will be expressed in a quickening of the 100m floats, which will improve the overall 3,000m time.
Let’s take a brief overview of the physiology of acute recovery from high-intensity exercise. During intense running, the muscles produce large amounts of lactate, which is not a foe, but a friend to runners, as it is a super fuel. But we need steady conditioning to accept large doses of lactate as fuel. Otherwise, it produces waste metabolites.
The fitter a runner becomes, the more apt they’re able to use lactate efficiently. In contrast, less fit runners are not as conditioned to processing high levels of lactate as a fuel, so it slips from the muscle tissue and builds up in the bloodstream — causing an acidic environment called acidosis, turning off muscle fibers and slowing runners down.
The quickening of the 100m float speed indicates increased efficiency in lactate-as-fuel usage.
Do this workout once-a-week for six weeks. Introduce the session with a walk/jog as needed so the 400m reps are performed at the desired speed, then in future runnings, seek to keep the 400m speeds stable and strive to improve the 100m float periods. It will be difficult to manage the first 1-4 workouts, but significant gains will be had somewhere in the 5th or 6th rerun of this session.