How (and Why) to Add Extra Interval Reps

To do 20 400-metre repeats – yes, 20! – you’ll need tenacity and proper pacing.

A few years ago, a team of researchers combed through four decades of training studies to determine the most effective type of interval workout. The sweet spot for boosting aerobic fitness, they determined, was repeats that lasted three to five minutes each. So it was a surprise when the leader of that team, Mayo Clinic physiologist and training guru Michael Joyner, promoted a very different workout in a recent blog post.

Joyner suggested building up to doing 20 x 400 metres with a 200-metre jog after each repeat. Depending on your pace, each repeat might take somewhere between one and two minutes – shorter than the ‘optimal’ length. But the benefits, he argued, are “as much spiritual or philosophical as they are physiological”. So many stops and starts demand a hyperfocused state of mind and cultivate a meditative rhythm – and the physical challenge of completing the workout leaves you with a sense of mastery that you’ll bring to your next race.

This type of workout has a long and colourful pedigree. Emil Zatopek, who won the 5000m, 10,000m, and marathon events at the 1952 Olympics, reportedly ran 20 x 400 with 200-metre recovery every day before the 1948 Olympics, with hard 200-metre repeats before and after. Before the 1952 Games, he upped it to 40 x 400 daily. Jim Ryun, the most recent American to hold the mile world record, did the same workout in high school in the 1960s (and also did as many as 40). The 400-metre repeats were ideal, Ryun says, because “it’s short enough that you can run pretty fast, but you can recover and do it again and again”. Here’s how to harness the power of repetition in your own training.


Build gradually. Start with a more modest workout like 10 × 400, and repeat the workout every week or two, adding two to four repeats each time. Plan to hit 20 × 400 four to six weeks before a goal race. Alternatively, if you’re focused on shorter races like 5Ks, you might start with shorter, speedier intervals, progressing from 20 × 200 to 20 × 300 to 20 × 400, each time with a 200-metre jog recovery.

Be creative. Of course, there’s nothing magical about 20 × 400. While the symmetry of running exactly one lap around the track is appealing, you can also hit the roads or trails for a comparable session like a 20 x 1:00 hard, 1:00 easy fartlek. The exact details and terrain aren’t the point. One year while preparing for the summer track season, my teammates and I did a weekly Saturday morning hill workout that started with six ascents of a steep 55 second hill in late winter and progressed to 20 in the spring – with the pace undiminished.

Pace yourself patiently. How could athletes like Zatopek and Ryun possibly run 40 repeats? It’s simple: they ran them at a sustainable pace. Learning to distribute your effort over the course of the workout is one of the keys to success. One helpful trick is to divide the workout into four sets of five repeats each, with an extra 200 metres of jogging after each set. (This will also help you keep track of how many you’ve done.) Run the first set at 10K pace, then try to make each successive set a little quicker. Still, the overall effort should remain controlled. Joyner recommends following the ‘no-bend-over’ rule: if you have to stop and put your hands on your knees to catch your breath before starting your recovery jog, you’re going too hard.

Keep perspective. As hard as this workout sounds, it’s worth remembering that 20 × 400 only adds up to about 8K of hard running. The actual distance covered isn’t crazy; it’s the mental challenge of breaking it up into so many pieces that makes it daunting. That’s why Joyner emphasises the importance of finding the right headspace, with a mix of self-control, relaxation and focus. When you can finish the workout feeling tired but triumphant, rather than shattered, you’ll know you are ready to race.


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