Klaas Lok' Easy Interval Method: A unique interval-based training system
Everyone in the 20th century: Long and slow mileage is the only way. Klaas Lok: Hold my beer.
WEEKLY WISDOM: THE EASY INTERVAL METHOD
First and foremost, I couldn’t have wrote this post without the rich and concise book that is Easy Interval Method by Klaas Lok, which you should absolutely read! It will cover this method in a lot more detail than I do. I’m just here to open your eyes to a very interesting and thought-provoking style of training.
WHO IS KLAAS LOK?
Klaas Lok was a former professional athlete from the Netherlands who competed at the highest level in the middle and long distance events, winning a total of 24 national titles—six of which were in cross country—with personal bests of 3:38.8 in the 1500m and 28:24 in the 10000m. Additionally, in 1980, Lok finished second in the European Indoor Championships 3000-meter and 20th at the World Cross-Country Championships. He was not an insanely talented athlete like that of Steve Ovett or Sebastian Coe, legends of his time, but he attributes a large amount of his success to training by the Easy Interval Method (EIM).
OVERVIEW OF THE EASY INTERVAL METHOD
The EIM, founded in the Netherlands by Klaas’ coach, Herman Verheul, was a new and unique style of training which was far different from the traditional methodologies of the time where the emphasis was heavily on steady-state/high-end aerobic development with relatively infrequent doses of high intensity/anaerobic work (thanks in large part to misinterpretations of the work of legendary coach Arthur Lydiard1). Rather, the EIM is a high frequency, micro-dosed approach to training characterized by near-daily bouts of fairly relaxed and light aerobic intervals (200-2000m), or intervals that predominantly improve ones aerobic physiological fitness, inspired by the work of notorious interval-based coaches Woldemar Gerschler and Mihály Iglói2 of the post-war era as well as four-time Olympic champion, Emil Zatopek.
What these coaches, including Herman Verheul, figured out was that they could condition their athletes aerobically to a high, world-class level through the use of intervals instead of enforcing a lot of time on feet. In other words, they could produce very similar effects to the longer steady running with this broken up work. If you think about it, this is exactly how competitive swimmers train; the majority of their swimming is done with intervals ranging from 25 to 400 yards/meters, give or take, with relatively short rest periods between reps. Otherwise, to build aerobic fitness, swimmers would have to swim, say, two hours straight which would be an absolute nightmare. Who would want to do that?! Coming from a competitive swimming background, I can tell you I sure wouldn’t!
Going back to what the EIM entails, not only is there the frequent aerobic interval running but there’s also frequent racing to build up ones anaerobic fitness and racing prowess. The timing of this depends on the individual and the peak race distance, but Klaas suggests that you could even race once a week under this method! This is in line with his recommendation to stick to a maximum of one harder, anaerobic session a week (aka it doesn’t have to be a race). Notably, Klaas mentions in his book, Easy Interval Method, that the serious runner should have periods of zero harder anaerobic workouts, specifically referring to “buildup” periods in which the emphasis is predominantly on aerobic development (e.g., the base-building phase). The reason for the general lack of anaerobic work in this training method is that, through the early findings of Dr. Jan Olbrecht and later Klaas’ coach Verheul, this training can be a detriment to performance if dosed incorrectly (overly high intensity and/or frequency).
One thing you might be wondering is “what about the long run?” Klaas believes that the aerobic intervals are largely sufficient for developing aerobic prowess, but does state that for the marathon, one should still use those longer long runs, albeit with surges instead of just straight easy. However, for distances below the half marathon, this isn’t really needed. As a matter of fact, he suggests the following ranges for these events:
1500m-5k: 6-10k w/ surges every 5-6 minutes
10k-15k: 8-12k w/ surges every 5 minutes
PACE GUIDELINES
As mentioned above, the aerobic intervals can range from 200 to 2000 meters in length. Per Klaas’ instructions, these are the paces and rest periods he advises for the various interval distances:
200m - 1500-3k pace w/ 200m walk-jog-walk rest
400m - Roughly 10k pace w/ 400m walk-jog-walk rest
1000m - Roughly threshold pace (between 10k and half marathon pace for most runners) w/ 800m walk-jog-walk rest
2000m - Steady to marathon pace w/ 800-1000m walk-jog-walk rest
Notably, he also advises that you run plenty of 100-meter repetitions at 800 to 1500-meter pace to prime yourself before workouts and bring some bounce to your stride. You can also do these after workouts as an extra stimulus, at that point largely developing fatigue resistance and less so power/top-end speed.
When it comes to the walking, it is suggested to use 10-30 seconds (or more) of walking on both ends of the recoveries.
EXAMPLE
Pulling directly from the book, here is an example two-week schedule for a 10k runner doing six sessions a week who wants to race regularly:
Week 1
Monday: 8-10x400m
Tuesday: 6x1000m
Wednesday: 15x200m
Thursday: 6x1000m or 4-5x2000m or moderate endurance run of 35-45’ w/ surges
Friday: 6x1000m or 10x400m + 3-5x100m
Saturday: Rest
Sunday: Endurance run w/ surges + 3-5x100m; if fit and race shape needs a boost, run 25-30’ fast; if you have run many races, it’s better to choose moderate or easy 35-50’
Week 2
Monday: 10x400m
Tuesday: 6x1000m + 3-5x100m
Wednesday: 15x200m
Thursday: 6x1000m + 3-5x100m
Friday: 8-10x400m (extra easy)
Saturday: Rest
Sunday: 10k race
As you can see, every single day of running has some intensity. It may sound crazy, but when you consider the rest periods following these intervals and the relatively slower paces, it becomes reasonable for the competitive athlete. For a less experienced runner, Klaas offers lighter programs that have as low as one to two sessions a week, so don’t worry, there’s something for everyone! Importantly, Klaas emphasizes the importance of running slower than you think in these intervals, as the body has to adjust to the high frequency. This is especially crucial for those who are new to this training style.
PROS AND CONS
So, you’ve gotten a general overview of the EIM, but let’s go into the good and the bad of this training style...
PROS
Develop and maintain year-round reactivity and mechanical efficiency
Less mechanical loading on the body (aka lower total ground reaction forces) and consequently, lower risk of injury (once adapted)
If you’ve got poor form and face recurring injuries, this could be great for you. Of course, you should still address your form and work to improve it as is done in many other sports like swimming and golf.
Develop high proficiency in lactate clearance
If you like intervals and/or hate solely easy runs, this could be quite enjoyable
Improve your racing abilities (if you choose to race frequently)
Lighter training program
Particularly well suited for older runners and masters runners
Faster recovery from races and better suited for round-based competitions
Because of the high frequency of faster running, you are better equipped for racing to your ability several times over the course of a short timeframe
CONS
Intervals every day could get pretty monotonous
If you like the long steady work and/or dislike intervals, you might not enjoy this
Because very few use this method, it’s really a solo-wolf training style (unless you can somehow convince your friends/peers to join you)
If you have further questions, please ask me of course! See my contact information at the bottom of this post; I would love to help.
Next up on All Things Running… Don’t make this one coaching mistake!
SUPPORT ME
Follow me on my other media through this link.
If you want personalized coaching and/or training advice, I’d be happy to help. You can email me at jacobreesmontgomery@gmail.com or send me a direct message on Instagram.
A lot of people mistook the Lydiard style of training as just a lot of mileage and slow distance running, including long slow distance runs, with little to no anaerobic work. However, a lot of the mileage his athletes ran was fast in nature, despite the high durations, during the six months or so of aerobic development. Additionally, this period of aerobic development was always followed by an anaerobic development period comprised of Lydiard’s hill drills (e.g. bounding) and intervals SIX times a week; only one endurance run a week was used to maintain the aerobic gains from the prior period. Many people overlooked this fact and continue to do so.
I’ve written about Igloi and his training style in a separate blog post which you should absolutely read!!!