July 2020 - Q&A with Klaas Lok – 24x champion of the Netherlands and author of Easy Interval Method (article on mastersmilers.com - this website is no longer active)

  1. You were a cyclist rather than a runner in your youth. What led you to get into running at age 16?
    I wasn’t really a cyclist: I just had to bike about 22 miles round trip to school everyday. I started running due to an older brother: he was an ice speed skater and cyclist. He ran a 5k course now and then as extra training. One day I joined him, I could keep up with him and enjoyed it. After that once every week I ran this course, trying to run faster every time. However, I didn’t do this all year through, perhaps just 6-7 months a year. Only at age 18, I began running regularly with 3 sessions a week.

  2. When you first started competing as a runner, you didn’t necessarily demonstrate a great deal of natural talent, despite the fact that you probably had decent aerobic fitness from cycling. In your book, you compare yourself at age 18 to Said Aouita who also only started training as a runner at age 18. Can you talk about your own “natural talent” and the results you were ultimately able to achieve?
    Well, Said Aouita, former Olympic champion 5000m in 1984 and former world record holder over 1500, 3000 m, and 5000m, was a soccer player and - as the story tells (you can find it on the internet) - aged 18, during a fitness test of his soccer club, he ran his first 3000m in 8:15.
    I myself ran my first 3000m in 9:20, also as an 18-year-old, after already 2 years of irregular training once a week and six months training three times a week, as described above. Aouita ended up with a PB of 7:29, I managed to run 7:51 (indoor).

    Also compare, for example, my 200m pb of 25.6 seconds to the 21.7 of Steve Ovett. And at 400m I was about 5 seconds slower than Ovett. But at 1500m, my time was just 7 seconds slower: 3:38, while Ovett did 3:31.So, my talent compared to the talent of Olympic champions Ovett and Aouita was quite moderate.

    In my first year as a junior, I trained as I explain in question 3 below, with moderate success: 800m in 2:00, 1500m in 4:16, 3000m in 9:20, 5000m in 15:56. Nothing to get excited about.
    But once I changed to the Easy Interval Method as a 19-year-old, I became Dutch junior champion and ran Dutch junior records within nine months time. And in the years after I managed to run respectful times.
    I would also like to mention that after my 3:38 at 1500m I experimented with steady runs and 2 times a week hard tempo training: my time at 1500m went down with 7 seconds to 3:45 and at 10,000m I performed almost a minute slower.

    I am sure that the easy interval training has been crucial in accomplishing a higher level than I would have reached if I had been training as most of my competitors did, with a lot of steady state training and many hard anaerobic sessions.

    3.  You initially trained with the more traditional approach of mixing a few hard anaerobic sessions with slow steady state runs. When you went to university, you started training with coach Herman Verheul, who was a proponent of the Easy Interval Method. What did you think of this style of training when it was first introduced to you? How long did it take you to adapt to this new approach?
    Actually, before I started training under coach Verheul, I ran those runs of 5K and 8K rather fast and nearly always sprinted the final 400m. In addition, I did two anaerobic sessions of 10x200 or 4-5x400m. Plus a race almost every week. So, my philosophy of training was: suffer as much as you can, and your body will get stronger…

    I was surprised that under coach Verheul, I had to run the intervals much slower. However, other runners had already been successful with this training approach and furthermore, I didn’t know so much about training principles so I didn’t question it and just accepted it.

          But actually, the total load of this way of training wasn’t that light compared to what I did before, because instead of just
          4x400 fast, I now had to do 10x400m relaxed. Also, the warmup and cool down was longer, so the total mileage was
          more than double. Above that, I now did 6 sessions a week, while before I did 4 or 5. After a little bit more than two
          months I ran a pb of 1:57 at an 800m indoor race, without doing any anaerobic session. So, this convinced me.

  1. Can you give a high-level summary of the differences between the Easy Interval Method and the more traditional approach to training that most middle- and long distance runners follow?

          The basic training in many schedules consists of several long, mostly steady runs: easy, moderate, sometimes fast, often
          complemented with two weekly hard interval sessions and some shorter speed work.
          In the Easy Interval Method, however, nearly all long runs are replaced by aerobic sessions of 1000m (sometimes 2000m)
          and instead of two hard interval sessions, we just do one weekly hard session (a mix of speed, aerobic and anaerobic
          tempos), although these heavier workouts are not done in track race season. 
          Apart the 1000 (and sometimes 2000m) interval training, we do shorter relaxed interval training: 200 and 400m’s.
          Regarding longer runs: depending on race distance now and then you can find a longer run (preferably with a few surges)
          in a schedule.

          Interval training is key to perform at one’s best level. Top runners do 10-12 sessions a week, often with at least 6 interval
          sessions. So many of these runners will indeed get the best out of themselves. But take, for example, a more or less
          average runner who has 5-6 sessions a week. When these runners try to copy the schedules of top-runners, they will
          copy the three steady runs, which leaves only two sessions for interval training (and 1 race). But if you really want to get
          the best out of yourself, then just two interval sessions is not enough. With easy interval training as their basic training,
          they can double their interval training. This way of training is more effective, because with a session of 6x1000m, eg, you
          have speed (much closer to race speed than when you do easy long runs) - so also near proper running economy), and
          aerobic training in one session!

  1. To give our readers an idea of what the Easy Interval Method looks like, can you walk me through an example of what a training plan would look like for someone like me if my goal is to break 2 minutes for 800m or 4:05 for 1500, (I will be age 49 in December, ran 1:58 and 4:03 at age 45 and currently follow a more traditional approach of 2 interval workouts, 1 long run and easy recovery runs or cross training on other days).
    I would need two pages to give you a thorough schedule, which I am happy to do, outside this interview. I am convinced that you will experience after 3-6 months that you will feel more power in your legs and experience a smoother running style. Just read the story in my book about Dutch 800m-runner Bram Som (pb 1.43.45), WC finalist 2009. After years with high mileage and struggling with injuries, he changed to easy interval training under my clubmate Ruben Jongkind. With just 1/3 of the training load of before, he more or less equaled his pb at 800m, and beat his times at 1000 and 1500m. He reported his running felt more relaxed, smoother and stronger.

    In the context of this interview I will just give some guidelines for you as an 800 and 1500m runner (not the 400m-type 800m runner).

    As you have already understood from my answer to question 4, first thing to do is replace all your long and recovery runs by relaxed 1000-400-200m interval sessions (as guidance I have a table with times in my book). Only in an aerobic build up period I advise a few cross country (or road) races and/or moderate runs of 4-5 miles with a few surges, once in 1-2 weeks.

    As an 800m runner, add fast, but relaxed 100m’s once a week (20x100m). Because you also run 1500m, I would suggest to do those once every other week. Instead of a separate workout you could do 5x100m every other day.

    When preparing for race season: combine your two weekly anaerobic workouts into one, but only do about 60% of the sum of these hard tempos. This could be done in a so-called mixed session.

    Next you should not do any long runs in the final 5-6 weeks before your key race (a pure 800m runner doesn’t do any long runs for about 2 months). The 4-6x1000m easy interval is the longest you run. You even skip these 1000m’s in the final 7-10 days before your key race.

    In race season run different distances of 800, 1000, 1500, 3000m and minimize the number and length of your anaerobic workouts. When they are racing every week, many runners don’t need additional anaerobic workouts; some, however, could benefit of a short, one time anaerobic set of reps, like 5x200m fast with just 30 seconds jog between the reps. Some short speed intervals (100-150m), however, are allowed. No anaerobic workouts when doing two races a week, no anaerobic workouts in the final 10 days before the key race.  
  1. You mention that there are similarities between Verheul’s Easy Interval Method and the training methodology of the famous Hungarian coach Igloi (who coached Bob Schul, Jim Beatty and I also know Johnny Gray followed the Igloi method). Can you talk about the similarities and differences between Igloi’s approach and the Easy Interval Method?
    The similarity is that both methods consist of mainly interval training. But the difference is that Igloi let his runners often do them faster, many more reps in every session and often two workouts a day. Verheul however, wasn’t such a fan of two workouts a day for his runners who weren’t professional runners, but students or having a regular job. (I was one of the few runners who did an extra morning session, now and then.)
    Igloi also had different distances and speeds in every session, while Verheul chose for doing 1 speed and 1 distance in most sessions. Only in a mixed session once a week (in a so-called fartlek in the forest), Verheul implemented different speeds and distances, aerobic and anerobic. More about this mixed session further on in this interview.
    Another difference is that Igloi didn’t prescribe any long, aerobic interval training, while Verheul implemented regular high end aerobic interval training like 6x1000m.

    Some example sessions of Igloi can be found here: http://www.racingpast.ca/john_contents.php?id=146
    Various paces which were described by Igloi through subjective statements such as easy, fresh and fast good.
    1. 15x100, 15x150, 10x400, 15x150, 15x100m
    2. 20x200 in 29, 2x800 in 2:00, 15x150, 6-8x100;
    3. 20x100, 5x400 in 57, 10-15x100, 15x150, 5x400 in 57.
    And these three workouts in one week!
    Igloi prescribed short recovery jogs, like 200m jog after a 400m.

    Compare these workouts to the next two relaxed workouts of Verheul:
    - 3x100m surges, 10x400m in 70 secs, with 400m recovery.
    - 3x100m surges, 6-8x1000m in 3:15 with 800m recovery.

    Verheul started in his first year as coach with faster paces, but found out that running a bit slower gave better results!

  2. You also talk in the book about the fact that a lot of people misunderstand Lydiard’s methodology and that his approach also calls for more speed work than most people realize. Can you discuss.
    The long runs of Lydiard were mostly done in a hilly environment, and quite intense: hill up (I guess for around 3-5 minutes), next recovery while running downhill. So not one steady pace as many runners do in a flat environment. Here (https://www.brianmac.co.uk/articles/article005.htm) the so called slow long runs of Lydiard are even called “a fallacy” because “much of the aerobic running was close to the anaerobic threshold.

    Recently, I talked to Hans Keizer, physiologist and former national coach and team physician of the Dutch Athletic Union. He is also husband of Ilja Keizer-Laman, who finished 6th at the Olympics 1500m (4:05.1) in 1972. He told me he has also been ‘misled’: end of 1968 Arthur Lydiard lectured in the Netherlands and that winter many of the top middle distance runners in the Netherlands ‘copied’ the Lydiard high mileage approach: lots of steady state training... not in a hilly environment but on flat courses, because a geat deal of the Netherlands is quite flat. All these runners performed poorly in next summer season. Only at the end of the summer, due to running races and lower mileage, the equaled their pb’s.
    Hans Keizer: “Only later we learned that Lydiard’s endurance runs were actually high-end aerobic interval runs of up to about 800m up-hill with a recovery run back down. Due to the flat environment in the Netherlands, for us it became a steady slow run with no variation in intensity. When you do slow, steady state training, you will ‘untrain’ your fast type 2 muscle fibers”.

    So, we can conclude: Lydiard’s actual training resembled more our extensive easy interval workouts over 1000m…

  3. According to your book, Faith Kipyegon follows the Easy Interval Method. Who are some other notable elite and masters athletes who have achieved success with this training method?
    It started with runners in my club who reached national level: My clubmate Joost Borm and I ran 3:38 at 1500m. Another clubmate, John van der Wansem, was one of the leading masters in the world from 1990-2005 and has achieved two 40+ and one 55+ world records. Other succesful masters: Edo Baart (European champion), Erik Driessen (Dutch master champion), Jan-Pieter Mondriaan (Dutch master champion).

    Most successful master is German runner Silke Schmidt, who is living in the Netherlands and is coached by my former clubmate Lex van Eck van der Sluijs. In 2015 she was named ‘IAAF Female Master Athlete of the Year’. In that year she won four world titles and ran seven world records in the 55+ age category.

    Other notable runners coached by Lex van der Eck van der Sluijs were Patrick Aris (3000m in 7:57, 5000m in 13:47), Huub Pragt (Dutch marathon champion), Joke Kleijweg (Dutch 10,000m champion, winner of the 1991 Rotterdam Marathon in 2:34:18, Carlien Harms (Dutch cross-country champion, Dutch record holder over 10,000m in 32:22.8) and Erica van de Bilt (5000m national champion in 15:23.27). Finally, Wilma van Onna won several big road races in America while being coached by Lex. These runners may not have been right at the top of the world’s elite but they all improved significantly after adopting the Easy Interval Method, and achieved times and success that they never thought possible.

    About 70 Dutch titles have been won by runners of just 2 clubs, where the easy interval training has been used as basic training. Also 10 Dutch records have been beaten by these runners. And many other runners have first been struggling for years at a lower level, and next surprised themselves and their competitors. I give some remarkable examples of such runners in my book.

    In 2009, my clubmate Piet de Peuter moved to the small Kenyan village of Keringet (approx 1000 inhabitants), which sits more than 2600m above sea level. He initially went to Kenya to escape the busy Western lifestyle and help the local population, but he soon found himself coaching a group of talented young athletes, including the then unknown 15-year-old Faith Kipyegon, now Olympic and world champion at 1500m. Piet de Peuter produced several other world-class runners: Geoffrey Kirui (10,000m in 26:55, marathon world champion in 2017). Mercy Chebwogen and Gilbert Kirui (brother of Geoffrey) both won medals at the world junior championships over 3000m and 3000m steeplechase respectively. Gilbert’s pb at the steeple is 8:06. Other successful runners from Keringet and coached by Piet de Peuter: Alfred Ngen (bronze medal WC Cross juniors). John Langat (half marathon 1.00.24), Moses Koech (half marathon 60.01), Joyline Cherotich (5000m in 15:17). (Piet de Peuter stopped coaching these runners end of 2021.) 


  1. Do you think the easy interval approach works well for masters runners?
    Ask the masters I just mentioned and they will tell you that they run faster since they changed to training with easy intervals. Not only because of this, but also for another reason I am sure that especially master runners will benefit using this approach: master runners have lower hormone levels, so their recovery is not as good anymore as this used to be in younger years and they will be more prone to injuries. Most ‘easy-interval-runners’ report fewer injuries (be aware: you have to adjust to interval training first!) and feel they better preserve their reactive running style and speed.

  2. What are the main advantages of the Easy Interval Method?
    The following is feed back from runners, how they have experienced it:
  • Lighter training program.
  • More fun in training.
  • More reactivity in their legs (which gives a better running economy and improved biomechanics when running); better finishing sprint; feeling more powerful and lighter on their feet.
  • Most runners report fewer injuries (once used to this way of training).
  • Better training for older and masters runners to maintain speed and reactive running
  • Faster recovery after races.
  • Able to run more races.
  • Looking forward to each training session.
  • A middle-distance runner only needs to do around 30% or less of the heavy anaerobic training compared to ‘traditional’ training runners.
  • Much quicker return to fitness after a period of not training, after illness or injury  
  1. Explain the concept of “reactivity”
    When making a stride and landing on one foot, your muscles, tendons and foot arch are being stretched. This causes a certain pretension which helps to ‘propel’ you forwards in the next stride. This elasticity is also called reactivity. With mainly doing easy interval training, your reactivity will be better than mainly doing steady state training and hence your race times.
  2. Can you explain what “mixed sessions” are and how important these are to the overall training program?
    A mixed session in our training method is a so-called fartlek in the forest. No measured distances, no clock, everything just on feel, like Igloi did. It was a mix of all distances from 10 seconds up to 10 minutes, a mix of speed, aerobic and anaerobic tempos, during 1.5 tot 2 hours. With many all-body exercises in between the tempos. I give an example of such a workout in my book.
  3. Improvement as a runner actually comes not during workouts, but when we recover and achieve “super compensation”. How do runners recover when they are doing intervals nearly every day of the week?
    With easy interval training, you are still doing quality workouts and meanwhile recovering, due to the fact that the training is light.
    And, can you call it recovery when you do several slow runs a week after a heavy race? Slow runs that destroy your reactivity and race speed coordination?
    Furthermore, how about recovery when doing two hard anaerobic workouts a week, while it has scientifically been proven that you need 5-6 days to recover of such an effort?

    14.Do you still personally train / compete?
    I am not coaching anymore and I also don’t compete. I am retired as a teacher and I enjoy traveling.