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                          Attention: For Dutch runners: a Dutch edition can be found here.

                          Attention: In December 2022, an update of the hard cover book and an eBook of the Easy Interval Method
                          has been published (hard copy contains 26 pages more).
                          Ebook is is available at Amazon and Apple; hardcopy only via Amazon.
                          The update got extra schedules 3-4 sessions a week for 1500m, 3-4-5 sessions a week
                          for 800m,
                          A chapter dedicated to masters (with a schedule of USA 60+ WR holder Dan King
                          who applies regular cross training). 
                          A chapter regarding hill training and a chapter with Q & A.

Download a preview here (with a summary of what you can expect in the book + many reviews of enthusiastic readers)
Order at Amazon (hard copy + eBook): here.
Order at Apple in USA:  https://books.apple.com/us/book/id6445219235
Order at Apple in UK: https://books.apple.com/gb/book/id6445219235
Oder at Apple in Australia: https://books.apple.com/au/book/id6445219235
Order at Apple in Canada: https://books.apple.com/ca/book/id6445219235
For Apple in 27 other countries: fill in your country domain extension, for example DE, FR, IT instead of US.


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 at Amazon: 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
More:

- Interview with Peter Brady on mastermilers.com
- (26 Jan 2021) https://www.fastrunning.com/running-athletics-news/looking-for-igloi-in-the-21st-century/31745
- (17 March 2021)  Book Review on Fastrunning: EIM by Klaas Lok
- Experiences of runners in the Easy Interval Group on Facebook
- (30 Dec 2021) Article about the training of Ingebrigtsen in which Easy Interval Method is also been discussed  
- (6 Sept 2023) Article of Tom Shax, in which he discusses his experience regarding the benefits of EIM compared to 80/20 approach
- Youtube video in which Patrick Martin discusses his experience regarding the benefits of EIM compared to 80/20 approach
Article of Nate Jenkins: The Importance of Running Specific Musculoskeletal Strength

- Research by Belgium exercise physiologist Eline Lievens found that runners with around 50-50% distribution of slow- and fast twitch fibers need more recovery time compared to runners with around 80-20% distribution. Click here for the article.
She told me: "It is indeed true that top runners will probably have a slower muscle fiber type than the 'average' runner. The average runner, with more type II fibers, will have to recruit those fibers to make adjustments. The type II fibers can be trained more aerobically, but this will not be possible through slow endurance running, it will require a little more intensity."

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.


Some advantages of the Easy Interval Method as experienced by users:
* Lighter but more effective 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 power and lighter on their feet.
* Improved lactate clearance helps you to run at higher speed with lower acidification.
* Most runners report fewer injuries (once used to this way of training).
* The best training for older and master runners to maintain speed and reactive running.
* Fitter and better prepared before races.
* 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.


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.
Read the article: Why the Easy Interval Method could be better than a polarized approach for 'normal' runners )




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.
- Dan King ran American records as a master 60-64.

Testimonials of top as well as every day runners:

International:

- Tim N (1951): "I enjoy the aerobic interval training and felt faster and stronger as a result. Last Sunday I was delighted to win individual category bronze and team gold at the British Masters 10k Championships, so EIM is definitely working for me.
Thank you Klaas Lok!"

- Russ Mullen (UK): "After 10 years of running and not improving anymore (in fact: getting slower), I changed to the EIM. Within a year I beat all my pb's. I feel stronger, faster and I recover much faster after a race".

Peter Clarke: "Best running book I’ve read".

Aaron Lanning: "It's a fantastic method of training, very dynamic!"

Dan King (USA): "Of late my running has been outstanding. At 62 I set a new American record for the M60 road mile an then ran a 4:51.4 track mile in LA where my 1500m split time was 4:31.5. The best part of EIM for me is that I haven't had a single setback in 2021. I have been able to race a bunch and do a lot fewer anaerobic workouts as a result".

Giorgos Athanasopoulos (Greece): "The training was fun and not boring like the steady runs. After 16 weeks I did a 10k trial and I couldn't believe the result: 31:52, I literally crashed my PB, my legs felt so light and I was so relaxed during the whole 10k, I finished very strong and well. Thank you, Klaas Lok".

Rienk Davelaar: "The EIM is a fantastic method in terms of fun, injury prevention and in developing a smooth running technique."
Alex G: "Yesterday I beat my 6 years old 5k PB using the EIM. I ran 20:56, so if you doubt the method is working for the not very talented runner ((I am in my 50s), doubt no more."

Robert Cooper: "I’ve been using the EMI for over a year now, and it’s rejuvenated my running with the benefits that many others have stated, including better economy, strength, reactivity and being injury free".

Martin Daniel: "Thanks Klaas Lok, monumental work. It's fun, it's easy, and I am getting faster on only 4 sessions/week." 

Andreas Keil, Germany: " I'm totally convinced by the EIM. My threshold, endurance and power are on a new level. With the EIM I've got the feeling that I found the missing piece in my training.
At the Groningen 4Mijl (Netherlands) my goal was to run sub 20'. I ran 19:04 (2:58/k pace), 16th place. I never thought I could compete on such a level."

Steven C Cross (USA): "Where has this book been my entire running and coaching life?"

J
onathan Slaney: "The best kept secret in running!"


Netherlands

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!

Below some revies and comments that can also (except 3) be found at the bottom of this page on Amazon.

"The best kept secret in running!"
Reviewed in Canada on April 12, 2021
Jonathan S: "This book is certainly the best kept secret in running. It capitalizes on the biomechanical and neurological deficiencies of the physiology focused approaches like Daniels, Mcmillan, Canova, etc. The easy interval method is truly a gem. Forget the vaporflys. This is the best thing any runner could buy. For real!"

Ken S, USA: "As an over 65-year-old experienced runner, Easy Interval Method (EIM) is a preferred training method over the frequented stress and injury-related traditional methods of training. EIM benefits: less stress on my joints, improved recovery, performance, health, enjoyment from running. I highly recommend it."

Rodney M. (USA):
"The brilliance in this method of training (among other aspects) is the duration of the recovery. Another aspect that I like about EIM is that it is not just focused on aerobic/anaerobic metabolic conditioning but is looking at the effect the training has on the nervous system and the muscle-skeleton system. Lok talks about "reactivity" or "bounce" you get from more exposure to faster paced running. This increase in what exercise physiologists call leg spring stiffness helps with running economy. I highly recommend getting this book. This method is especially useful to those that want an alternative to high-volume training or want to gain the benefits of interval training in a gentler way. I think masters runners, in particular, would benefit well from this kind of programming."

Stephen C, USA: "Where has this book been my entire running and coaching life? This book encapsulates the why and how of what I experienced haphazardly. I’ve immediately switched to this methodology, and am using it for the many dozens of runners I coach. In my runners I’ve seen immediate results."

Comment of Manuel (USA): "This is simply the best training advice I have ever read. As a young runner I ran some pretty good times but always got injured from pushing my body beyond what it could handle. I discovered this book at age 65 and wish I had known this training approach 40 years ago. Klaas Lok has the resumé to speak with authority, and this book is a gift to runners of all abilities. I enjoy my training more than ever and have a “lift” in my legs I haven’t felt in years. Highly recommended!"

Reviewed in the United Kingdom, April 6, 2020
"A different approach"
"I like how its written, it’s quite informal and devoid of the' same old stuff' you get in most books. I am sure this book will be valuable to all types of runners but if your running is feeling a bit sluggish and you do not have a lot of pop in your legs you should really give this a read. Also, if you are not getting a lot of joy out of running this could help, as it is a really fun approach to the sport."

Dutchman Dirk Eidhof: "I am just a casual runner, for a few years already, but only for 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!"
Martin D. in the FB group: "Thanks Klaas Lok, monumental work. It's fun, it's easy, and I am getting faster on only 4 sessions/week."

E-mail message from Andreas K. (35 yr), Germany: " I'm totally convinced by the EIM. My threshold, endurance and power are on a new level. With the EIM I've got the feeling that I found the missing piece in my training. In a 4-Mile race my goal was to run sub 20'. I ran 19:04 (2:58/k pace). I never thought I could compete at such a level." In 2022, Andreas K (at age 36) prepared himself for his first marathon using the EIM, without any long runs, just EIM interval training. "As it was my first marathon I ran (too) conservatively (2:23:20 - splits 1:12:38/1:10:42), but I ran strong, controlled and the race felt quite easy."

"Truly differentiated training philosophy"
JG (United Kingdom):
"Very interesting book that proposes a training philosophy that is truly different from most other methods without going against the fundamentals of exercise science. The book is straight to the point and the main concepts are laid out very clearly and seem very logical. It would be interesting if the author could collaborate with researchers to further validate his method and contrast it against more traditional methods such as Stephen Seiler's 80/20 or Jack Daniels', especially for sub-elite runners."

"Unique approach"
Reviewed in the United Kingdom on December 16, 2021.
"Fed up running slowly for hours every week or killing yourself with hard fast intervals... well now there is no need... fantastic book!"

Dutchman Egbert Dokter:
"I am 45 years old and since applying the schedules in your book I am running my best times ever and feel fit all year round. Before, my pb at 10km was 39:51, which costed me lot of pain and effort. After applying your schedules (with just 3-4 sessions a week), exactly one year later I already achieved 37:30 on the same course and a few months later even 36:52. My half-marathon time improved to 1:21:05, where I previously ran 1:31:17. My most enjoyable experience however, was my first ever marathon in Rotterdam, where I finished in 2:58:52. I followed your 4x/week training schedule for 95% and felt fit and confident all the way up to the marathon."

"Highly Recommended!"
Reviewed in the United Kingdom on June 19, 2020
IanRunner
"I have to say this book is exceptional and nothing like I have read before and believe me I have read a lot of books about running! I have started getting a spring in my step. Doing easy interval sessions at varying speeds every time I run is great and really enjoyable. I will update you on the results after I have had a good length of time training with this method. Highly recommended."

"Run faster the easy way"
Reviewed in the United Kingdom on June 16, 2020
"Essential reading for runners of all abilities. As a keen club runner who has read many running books I was impressed by the honest and evidence-based approach to running faster presented here. What makes me keen to try this approach for myself is how much effort has been made to make the philosophy applicable to the reader, with multiple pace charts and realistic training schedules. A must read!"

Giorgos A. (Greece): "The training was fun and not boring like the steady runs. After 16 weeks I did a 10k trial and I couldn't believe the result: 31:52, I literally crashed my PB, my legs felt so light and I was so relaxed during the whole 10k, I finished very strong and well. Thank you, Klaas Lok."

Wessel H. (Netherlands) in the Easy Interval Method Group on Facebook:
I finished my first marathon following the EIM. Previous marathons with more conventional training: 3:30 - 3:13 and 3:03. In Valencia 2023, I ran (age 36) my first sub 3-hour marathon! Very happy with my result!😃. I really enjoyed the training and the marathon itself. Followed the marathon plan from the book the best I could. No slow long runs at one pace like usual marathon training. Also set a new PB on the HM a few weeks before Valencia (1:21:05).

Tom S (England): "Another EIM marathon success story (2.45.17 in Valencia 2023, a 4-minute PB). Most people I've spoken to seem surprised when I tell them that I averaged 50 miles a week for 12 weeks, no traditional tempos or hard interval sessions".

 

Why the Easy Interval Method approach is better than a polarized approach for 'normal' runners

In this video: (
https://www.youtube.com/watch?v=MALsI0mJ09I) Norwegian physiologist Dr Seiler talks about his research regarding the training of world-class endurance athletes. The title of his speech is: "How ‘normal people’ can train like the world’s best endurance athletes”.
I disagree: Normal runners can, but should not, train like the world’s best endurance athletes. Too much slower running reduces running economy for most runners (not mentioned in the research of dr Seiler) and is not the most effective way of training the aerobic abilities of all your aerobic muscle fibers (slow twitch and fast twitch).

Dr Seiler found that many top endurance athletes apply an 80-20% (easy-hard) division in their training, a so-called ‘polarized’ approach. Next, he states that ‘normal people’ should do the same. But he didn’t proof that this approach is the best of all, he only found that a 80-20% is better than a 50-50% division (50% easy and 50% hard), which is often applied by competitive club runners. His research is not wrong, but I think it is not complete. Easy interval training as a total approach has not been researched and many athletes who applied this – coming from polarized training – improved their performance.
Dr Seiler explains the polarized training in the graphs below:








According to these graphs, I can only conclude that Dr Seiler’s advice is that runners should perform 80% of their endurance running in low intensity zone 1 (= ‘can chat all along the way’). He calls this the green zone and advises to skip the aerobic zones 2 and 3, and perform faster sessions in the yellow and red zone. This is polarized training.

I oppose polarized training, especially for ‘normal runners’, and advise adding two green (aerobic) zones: green zone 2 (moderate) and 3 (high end aerobic). And I would call the yellow and red zones respectively zone 4 and 5.

Apart from this, the division 80-20 is not how, for example, double marathon Olympic champion Eliud Kipchoge trains. Have a look here:
https://www.prorun.nl/training/wat-doet-zon-eliud-kipchoge-nu-als-training/. In week 25-31 Aug 2017, 79km was performed in the green zone 3 and 15 km in red zone, of a total of around 210km: 94 of about 210km = 44%. 73km in green zone 3 of 210km total = 37%.
Indeed, Kipchoge performs some endurance training at a pace of 15km/h or slower, but he also goes up to a pace of 18.5km/h and has interval sessions like 18x1000m (at >2000m altitude!) at around marathon pace, which belong to green zone 3. Also, several of his so-called easy sessions are probably not easy all the way: when running at paces of 18-18.5km/h on a normal training day (not tapered and at > 2000m altitude, hilly environment), Kipchoge is running in green zone 3 
intensity (high end aerobic), not in easy zone 1 or moderate 2. I conclude: this is not 80-20% or polarized training.

Similarly,
 the training of famous coach Arthur Lydiard is often used as an example of building an aerobic base with long runs in zone-1 intensity, complemented with hard tempo sessions in yellow and red zones. However, this is incorrect: his so-called long, steady slow runs were often quite fast and performed in a hilly environment: 800m uphill followed by long down hills, so more an aerobic interval training in zone 3 intensity. Anecdote (in my book):




Why do I oppose a polarized approach?
I am of the opinion there is a caveat for many runners who are applying this 80-20 division. This caveat is the damage to their running economy caused by the slow 80%, which could be accompanied with loss of running economy (decrease of ‘elasticity’ and ‘bounce’). As a result, a runner may well increase their aerobic ability which, theoretically, might take off one minute from their 10km time. However, they may also lose their running economy which may make them two minutes slower. Thus, their actual performance could be worse.

Why is the running economy of world-class runners not killed off by all this slow running?
1) Carrying less weight than the average runner. For example, Eliud Kipchoge, weighs just 52kg. With a low weight it is easier to maintain a reactive running style, even when doing endurance runs.
2) Being born with a superior natural reactivity. World-class runners, especially East-African runners, often have 
shorter calf muscles and thus longer Achilles tendons: longer Achilles tendons give better running economy (free elastic energy). Research of Gary Hunter at the University of Alabama at Birmingham (in 2011) found a strong correlation between tendon length and running economy.
Hence, two reasons why East-African top runners can maintain a reactive running style. Even when they run slowly, they bounce every step. Unfortunately, an average runner does not have the advantage of the longer Achilles tendon but does have the disadvantage of carrying 10-20 kilo more which may be a reason for not being able to apply a similar economic, ‘bouncing’ running style as the top East-African runners do.
3) Apart from that: world-class runners train so much (including strides), that all their slow running is compensated by enough fast mileage (remember: Kipchoge runs 73km a week at 18km/h or faster). Furthermore, East-African runners often train in very hilly environment which may cause a higher intensity running uphill, hence also training their aerobic fast twitch fibers.

Caveat of polarized training
Another caveat of polarized training is this: if you train your anaerobic system too much (20% in the red zone 4 is what many runners apply… and that is too much in my view), then your anaerobic system will be come dominant too soon when running at higher paces. 
https://www.sisuracing.co.uk/post/what-is-vlamax-how-to-fine-tune-it-and-what-does-it-mean-for-your-anaerobic-capacity
“If your lactate production rate is high at max conditions (sprints), it is also relatively high at sub-max conditions (endurance events). Vice versa, if your maximum lactate production is low at max conditions, it’s also relatively low at sub-max conditions." I have experienced this myself and got similar feedback from other runners. Too much anaerobic training decreases the aerobic system: too soon your anaerobic system is dominant.

Train your extra aerobic engine!
Average distance runners have around 50% fast twitch fibers (which are partly aerobic), while most top distance runners have around an 80/20% or even 90/10% division slow twitch/fast twitch. On the website mentioned above: "By training at intensities just below the lactate threshold, it is possible to recruit the body’s aerobic fast twitch fibers, making them more aerobically capable and thus reducing the lactate production during exercise at low to middle intensities." So, if the ‘normal runner’ has 50% fast twitch fibers, why should they not exploit these fibers and add an extra aerobic engine? How to do this, how to train the aerobic skills of your fast twitch fibers? Fast but relaxed, short efforts in zone 3 will do the job! These efforts are skipped in a polarized training approached, but are a main building block in the Easy Interval Method, which is a total approach that does not first focus mainly on aerobic development alone but also on specific muscle strength and running economy at the same time, from day 1. Many runners who followed my advice reported that their aerobic endurance (+ running economy + times + enjoyment, amongst other things) improved after switching to training according the Easy Interval Method. That '50/50' runners should not do the same as '90/10' or '80/20' runners has also been proven by Belgian exercise physiologist Eline Lievens. In 2021 she found that most 'normal' endurance athletes with a 50/50 split in terms of slow- and fast-twitch muscle fibers require longer recovery time than the '90/10' or ' 80/20' athletes. I asked her if this also had consequences for the training. She gave the answer I expected: “The ’50/50 runner’ needs more sessions at a relatively higher speed in order to recruit the aerobic fast-twitch fibers, as too much slower training (easy) may not cause sufficient aerobic adaptations”.

No red efforts for slower runners
For slower runners (racing 10km and over) training in the red zone should be skipped almost entirely. Eg, for a 10km runner capable of running 50-60 minutes, training in the red zone (1500m intensity, which is far above LT intensity) is not very effective (and even counter-productive, as explained in paragraph 5), because in their 10km race they will run slower than their LT intensity. Extra sessions in zone 3 are much more effective.

So, do not train like the world’s best endurance athletes, do not apply polarized training, do not skip the high-end aerobic range of intensity. The reason this area is skipped in polarized training is that “it is too slow to achieve a major training effect, but too fast to get through unscathed.” Unfortunately, this is wrong: when training in the high-end aerobic zone (green zone 3) in a careful, smart way, you can very effectively train the aerobic fast twitch fibers and maintain, and even improve, your running economy, because the pace will be close to race pace. The Easy Interval Method shows you how to do this.

Download a preview of my book Easy Interval Method at dropbox and read enthusiastic reviews of ‘normal’ and top runners who applied the Easy Interval Method.
Or go to Amazon (for hard cover or eBook) or Apple (only for eBook).
(Dutch runners can buy the Dutch edition at:
Nederlandse hardlopers kunnen de NLse editie kopen via:
www.duurloopmisverstand.nl)

Some reviews here:

"The best kept secret in running!

This book is certainly the best kept secret in running. It capitalizes on the biomechanical and neurological deficiencies of the physiology focused approaches like Daniels, Mcmillan, Canova, etc. The easy interval method is truly a gem. Forget the Vaporflys. This is the best thing any runner could buy. For real!"

Another aspect that I like about EIM is that it is not just focused on aerobic/anaerobic metabolic conditioning but is looking at the effect the training has on the nervous system and the muscle-skeleton system. Lok talks about "reactivity" or "bounce" you get from more exposure to faster paced running. This increase in what exercise physiologists call leg spring stiffness helps with running economy.

I highly recommend getting this book. This method is especially useful to those that want an alternative to high-volume training or want to gain the benefits of interval training in a gentler way. I think masters runners, in particular, would benefit well from this kind of programming."

"Truly differentiated training philosophy"

"Very interesting book that proposes a training philosophy that is truly different from most other methods without going against the fundamentals of exercise science. The book is straight to the point and the main concepts are laid out very clearly and seem very logical. It would be interesting if the author could collaborate with researchers to further validate his method and contrast it against more traditional methods such as Stephen Seiler's 80/20 or Jack Daniels', especially for sub-elite runners."

"I’ve been using the EIM for over a year now, and it has rejuvenated my running with the benefits that many others have stated, including better economy, strength, reactivity and being injury free".

 








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.