The Easy Interval Method: short, relaxed repeats that get a little faster as you get fitter.

Short, relaxed repeats, with a short walk and an easy jog between each.

Klaas Lok won twenty-four Dutch national titles, from the 1500 meters to cross-country, on training that was mostly short, easy repeats. Lok’s case is that steady miles are the slow way to build an aerobic engine, and short easy repeats are the fast one.

So an easy day is repeats, usually of two hundred or four hundred meters, at a relaxed, controlled pace, with a short walk and an easy jog between each. Each repeat has a pace range from Lok’s tables, and anywhere inside it is right; as you get fitter, you move toward its faster end. The recovery is part of the session, and Lok is firm about keeping it. You stop at the planned number of repeats, even on a day you could do more.

Can you comfortably finish a 10 km race?

If not yet, you start where Lok starts everyone new to running: walk five minutes, then jog thirty seconds and walk three, four to six times, two or three days a week. When six feel easy, you pick the next stage yourself.

If you can, you start on Lok’s 10 km schedule: three runs a week, two of them easy intervals and one a run with surges. You run by feel until your own runs set your paces.

Lok wrote his standard sessions for fit runners under forty, then wrote a chapter for the rest of us: fewer repeats, and longer walks between them.

Lok explains the method himself.

• Easy Interval MethodKN Lok · 16 min · 2025

  Why an ordinary runner should not train like an elite one.

• Easy Interval Method: 2 main pillars of training for runners (slow long run is not one of these).KN Lok · 6 min · 2025

  Lok’s two pillars of training, and why the slow long run is not one of them.

• Klaas Lok: the easy interval methodRunner’s World Podcast · 45 min · 2025

  Lok, interviewed about the method.

Runners on the method, from Lok’s readers to a world record at sixty-one.

Lok keeps a hundred letters from runners on his site, most of them past forty.

Dan King ran a mile in 4:49.08 at 61, the first person over sixty to break 4:50, as Bring Back the Mile reported. Nine weeks of his training are a chapter in Lok’s book.

Lok makes the case for easy repeats over steady miles, and writes out every session.

Twospeed is how you follow the method, day by day.

Each run is written out: the repeats and the recovery between them, and, once your own runs have set your paces, a pace range from Lok’s tables. You start at the stage that fits your answer to that one question, and you can move up or down as your fitness improves, whenever you feel ready. If you use Strava, connect it and your runs come in from there.

If you want to lift too, your lifting comes from Mark Rippetoe’s Starting Strength: barbell lifts, and a little more weight each time. About Starting Strength.