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As a distance runner, are you tired of long, slow runs?  Do you often feel sluggish and flat and, despite doing your regular long runs, can never quite improve on your personal best times?  If so, The Easy Interval Method may be just the book for you!

READ enthusiastic reviews at the bottom of this page: https://www.amazon.co.uk/Easy-Interval-Method-Klaas-Lok/  AND
READ this great article written by Andy Waterman: https://medium.com/@andywaterman/reactivity-806ec9694fc3

- https://www.mastersmilers.com/qa-with-klaas-lok/
- https://www.fastrunning.com/running-athletics-news/looking-for-igloi-in-the-21st-century/31745
- Experiences of runners in the Easy Interval Group on Facebook

Written by Klaas Lok, a 24-time Dutch national champion, the Easy Interval Method challenges many of the usual training protocols and guidelines associated with distance running. Avoiding long runs in favour of relaxed, easy interval training, Klaas presents a strong and intriguing case to get athletes moving smoother, stronger and faster with fewer injuries. 

The Easy Interval Method contains detailed schedules for all distances from 800m to marathon. Using the principles described in this book, elite athletes have won many Dutch titles, set several national and World Masters records and even won Olympic and World championship medals. More casual runners have also surprised themselves by greatly improving their personal best times, even after years of stagnation. The book is a bestseller in Holland and is now available for the first time in English.

Easy Interval Method, a book with a training method that - according to so many runners who apply it - could be the best, the most pleasant and most efficient way of training.

Klaas Lok won 24 Dutch titles over 1500m upto 10,000m and cross country. He finished 2nd in the European Indoor Championships and 20th in the World Cross-Country Championships, both in 1980. He first published the Dutch version of this book (title: Het Duurloopmisverstand -  see souplessemethode.nl or duurloopmisverstand.nl) in the Netherlands in 2005.

Read on below the photo.

(Read the article by Adri Hartveld: 'Recovery after strenuous exercise generally takes about a week' . It supports the power of easy interval training.)

Striking successes
- Dutchman John van der Wansem ran 2 masters world records.
- German master runner Silke Schmidt (IAAF master athlete of the year 2015) did even better with 11 world records and 4 world titles.
- Olympic champion 1500m (2016) and world champion marathon Geoffrey Kirui (2017) won their medals when training with easy-interval advocates Piet de Peuter and 2006 European champion 800m, Bram Som.
- More than 70 Dutch titles have been won and 10 Dutch records broken by 'easy interval' runners.
- In several age groups, 6 different masters won 1 or more Dutch titles,

Testimonials of top as well as every day runners:

Jaap Valentgoed (1946) - Dutch masters champion 45+ marathon and cross-country in 1993

“During the first half of my career my training mainly consisted of long endurance runs with two fast interval sessions. Soon after changing to the Easy Interval Method  I noticed a change in running style and strength. My push-off got stronger and more reactive. I lowered my best marathon time by four minutes and won the Dutch masters title. In my opinion, this method is very suitable for masters runners, because with a lot of easy interval training one keeps reactivity at a good level, as I noticed myself.”

Erika van de Bilt (1971) -
Dutch 5000m champion in 2000; 5000m in 15:23

As a youngster, Erika was a talented runner. At just 17 years old she came from triathlon training to run a sub 38-minute 10km road race. Her coach at the time saw her talent in running and advised her to build up her mileage with a lot of steady-state running. Unfortunately, the result was that her running style deteriorated and she drifted into obscurity. She then changed her coach to Frans Thuys (coach of 1992 Olympic 800m champion Ellen van Langen and Christine Toonstra - former Dutch 10,000m record holder in 31:45). This resulted in a return to some sort of form, but Erika’s real breakthrough came after she switched to easy interval training. She went from being in the middle of the pack to a national champion over 5000m and lowered her 5000m time from 16:40 to 15:23, her 1500m down to 4:15 and half marathon to 1:14:21.

John van der Wansem (1950) - Former world record holder masters 40+ in 1990: 3000m (8:15.5) and 1 hour run (18,919m); world record holder masters 55+: 1 hour run 17,394m (2005)

John has been one of the top masters runners in the Netherlands for two decades (1990-2010). At the start of his career he won several medals at Dutch championships and made the national team.  Unfortunately, due to injuries he stopped running at the top level at only 25 years old. It wasn’t until he was 32 that he began training again. As a masters runner he was even more successful, breaking several world records.

What is most remarkable is that, as a young runner, John trained according to the Lydiard-method with very high mileage. At age 35 he switched to the Easy Interval Method and ran a personal best for 10,000m as a 38-year-old! When taking age-related performances into account, virtually all of John’s achievements during later years are far superior to those in his younger days. For example, 14:21.6 for 5000m as a 40+ runner is similar to a 13:49 for a 25-year-old - better than the 13:55.6 that he actually ran when he was 24. His 10km time of 31:49 which he ran as a sprightly 51-year-old is equivalent to a 28:20 of a 25-year-old.

In the book Easy Interval Method you will read a comparison of his schedules from the ‘Lydiard years’ of his early career with those from his years using the Easy Interval Method.   

Michiel de Boer - Dutch runner, improved his 3000m time from 9:41 to 9:07 and reduced his 5000m time from 16:58 to 16:09 within six months of switching to the Easy Interval Method

“The most important thing for me was that I have so much more fun in training since I started this method. The main reason for this is that I don’t need to do any long and boring steady-state runs anymore. Another reason is that my running technique has improved a lot; I land more on my
forefoot with longer strides and much better reactivity during my running! On good days I have the feeling that I am not just running but dancing. It is exactly as you have described in your book. Klaas, thank you for giving me so much more fun in running!”

Eric Borg (1967) - Top Dutch regional runner, 10km in 31:42
“I started running at age 25 and became a member of the local club, where I trained the usual combination of four steady-state runs and two hard interval workouts. At the beginning of 2003 I started with the Easy Interval Method. Since then I have so much more fun in running: no more boring, long steady-state runs and heavy anaerobic workouts (in the Easy Interval Method I do those just now and then). Now, nearly every workout is a positive experience. Almost sensational was the feeling of having great strength and reactivity in my legs during a race! At age of 38 I improved my time at 10km (31:42) and also ran personal bests at 3000m and 10 miles.

Remarkable also: I feel much fitter and I recover much quicker after a workout as well as after a race. More things worth mentioning: my stride is a bit longer, I have a much better finishing kick and I regularly receive compliments about my relaxed running style. Finally and perhaps most importantly: since changing to this method I have never had any injuries!”

Carlien Harms (1968) Dutch champion 10,000m & cross-country; Dutch record 10,000m 32:22.8, coached by Lex van Eck van der Sluijs.
‘During the first years of my running career I trained like so many other middle and long-distance runners: hard interval training on the track two times a week, one hill session and the rest steady-state running.

After only six months after changing to easy interval training, I started to run personal bests and from 1990-1992 I had my best years: winning Dutch titles and breaking the national record in the 10,000m with 32:22.

I am convinced that many runners can benefit from this way of training. Apart from running faster race times, there are two other notable benefits: a lower chance of injury and developing a much-improved running technique in a relaxed, natural way.” I noticed a renewed strength in my legs and the actual ‘running movement’ felt so much better and smoother which made it even more fun!

Rob Boot (1960) - Dutch runner and coach
“I have been training using the Easy Interval method for some time. Since changing to this method my speed has improved and I suffer fewer injuries. My best 10km time went from 46:20 down to 43:33 and I improved 10 minutes at the marathon. Klaas, thank you for your tips! For me it is clear: easy interval training is not just for top runners but also works for average runners like me who just want to improve their personal best times.”

Berthold Berger (1969) - Top Dutch runner, 1500m 3:43, half marathon 1:02:29
“I started running in 1978 as a nine-year-old and, up until to my 20’s, I trained according to the ‘traditional’ method: hard interval workouts and steady-state training, the latter mostly also fast. When I was 18-20 years old I trained harder and harder, but without satisfying results. When I reached the age of 20 this was all so frustrating that I considered quitting running altogether. In that year I struggled to realise times of 4:04 at 1500m, 8:49 at 3000m and 15:09 at 5000m.

In September 1989 I met Klaas Lok, who persuaded me to radically change my way of training. The results were astonishing: with only six workouts weekly, eight months later I ran 1500m in 3:53, 3000m in 8:17 and 5000m in 14:25. The following year these times were 3:43-8:08-14:09. I was stunned by this way of training.

I noticed my running became more relaxed, with better strength and reactivity and I learned to run more on my forefoot. Also remarkable was that my energy level and running reactivity increased to a level I never had before. This all gave me a finishing speed that I had lost in the years before, not just to my own surprise but also to the surprise of other competitors.

Bertrand Maas (1970) - Dutch 10km runner of 44:21.
“During the first two years of my modest running career, I trained according to ‘traditional’ schedules which I found on the internet. My best performance was a 10km in 52 minutes and half marathon in two hours. For this I had to ‘go very deep’ and I was not happy with my performance. The Easy Interval Method gave my fitness a huge boost. The next 10km race four months later was a pleasant surprise: 46:59 - five minutes faster! One week later I ran a half marathon in 1:47. Now I train three to four times a week and my personal best for 10km is 44:21.”

Lonneke Elzerman (1981)  Dutch 10km runner of 45:01.
“I started running when I was 17 and the first 15 years I mainly did steady-state training, mostly distances from 8-15km, just once in a while longer. In those years my best time over 10km was 51:09. Unfortunately, this way of training frequently brought me injuries. After changing to the Easy Interval Method, within a year I noticed I got stronger and faster, resulting in a personal best of 45:01 for 10km. It is such fun to experience the increase in speed and power in my running! Also, it doesn't cost me much effort to train in this way: after a workout I am satisfied and full of energy.”

"Dirk Eidhof: " I am just a (Dutch) casual runner, for a few years already, but only since six months I am running with real pleasure. The reason? The book of Klaas Lok. Since I apply this way of training my aerobic endurance has improved a lot and have run many PB's (43 min at 10K at the moment). Also important: training is not just 3x a week making mileage, but each time a different session. Highly recommended!"

More testimonials
‘I have been training for five months according to this method and all my race times are now better than last year.’

‘ My running now is like if I am flying over the asphalt, I feel more power in my legs; I just ran my fastest time in four years over 10 English miles. If only I had known all this before.’

‘ For more than 20 years I’ve been training in the’ old-fashioned way’, I had to warm up longer and  longer to come ‘loose’. Thanks to this easy interval training I feel ‘loose’ after 15 min. The biggest advantage is that my fun in running has increased; I experience almost no muscle pain anymore, even after a race! Because of this method I have also become much more motivated.’

A triathlete who focuses on running in the winter: ‘So striking is that I feel quite fit after my workouts, as well as after races. I almost never have a bad race anymore. This has been my best year in my modest sports career, to which this method of training has made an important contribution.’

Coaches from a track & field club in the Netherlands: ‘We have been using Klaas Lok’s Easy Interval Method for years now. We are enthusiastic about this training method, which contributes to fewer injuries to our runners.’

A biomechanist: ‘Steady-state runs are necessary from a biochemical point of view, but from a biomechanical point of view they are not the right way of training. The easy interval training in this book provides the ideal solution.’
Do more easy interval training, train your aerobic system at an higher level, feel more running power and speed in your legs!

A German translation will be available probably end of 2021: IAAF master athlete of the year 2015, Silke Schmidt, is working on that. Anyone who might be interested in helping to translate it into Spanish or French: please contact the author.

On this page you can read the first chapter of the book Easy Interval Method. It is the Foreword, written by by Russ Mullen, Sussex, UK.

"For most runners, the thrill and satisfaction of the simple act of running holds our attention for only so long. It is quickly consumed by the desire not only to run but to run faster! Whether you are a novice just trying to run an entire 5km or an elite dreaming of breaking 30 minutes for 10km, the goal is the same: it must be faster.

Running is one of the few sports where success and failure can be so black and white. Most people will never win a race against others. But you will never stop racing against yourself. If you complete the same course 10 seconds quicker than you ever have before, then you have undeniable evidence that you have improved. You’ve beaten yourself; you win. Conversely, the damning and bleak reality of failure is equally harsh. You didn’t win. But you will be back. All runners, no matter what their level, share these common feelings of success and failure and the single-minded determination that you will, one day, be faster than you were before.

I had been running competitively for nearly 10 years and managed to run times ranging from 9:35 (3km), 16:15 (5km), 33:29 (10km) and 1:15:11 (half marathon). I ran these in 2014 at 28 years old and had stagnated since then; actually, if brutally honest, regressed. I would constantly feel sluggish and slow and never ran a race I was happy with for three years. This all changed thanks to a completely different way of training: the Easy Interval Training Method.

I first came across the Easy Interval Method in December 2016 and was immediately intrigued. Within six months of training this way I have since run 3km in 8:59, 5km in 15:44 and 10km in 32:51. I have been truly amazed by these improvements as I’ve not only got back to my previous best but I have surpassed it at every distance I’ve run. I feel stronger, healthier and happier about all aspects of my running. You can read more about my story in chapter 2.2.

In this book you will read everything about this unique way of training. It is written by a man who has trained and competed at a level that most can only dream of. Klaas Lok won a staggering 24 Dutch titles from 1975 to 1985, and achieved times that, even today, would still rank him in the upper echelons of the world’s elite distance runners.

In the following pages Klaas shares his first-hand knowledge and experience of competing and training at a world-class level with a goal that all runners, no matter how fast or slow, can share: the goal to be faster than you were before. His insights provide thoughtful and unique ideas into the approach he personally used under the tutelage of his coach, Herman Verheul, and while there are no guarantees that following these ideas will turn you into a national champion, I do believe they will provide a thought-provoking insight into a unique and intuitive way of training that will lead to improved performance, health and enjoyment in your running, whatever your level."

Dutchman Adri Hartveld finished 5th in the Dutch Cross Country Championships in 1984 (photo below) and won the Dutch marathon title in 1986. He has worked as a physiotherapist in the UK since 1982 and, during that time, has assessed hundreds of runners with overuse injuries. As part of the assessment, Adri looked at both the athletes’ biomechanics and their training history. He also researched various training ideas and methodologies, including easy interval training.
Please scroll down below the photo to read a lecture that he gave at the University of Staffordshire in 2017.

From this lecture we learn that recovery can take about a week after a heavy effort (note: after an extreme effort (marathon) or several heavy workouts shortly after each other it can take longer!). We also learn that the best super-compensation takes place when after the heavy effort a light training session is completed once every two days.