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Welcome to the website dedicated to the book "Easy Interval Method". This successful training approach is truly unique, offering easy interval training as your foundational training in place of endurance runs. It is applicable for distances ranging from 800m to the marathon. Both elite and casual runners have greatly benefited. Numerous runners who switched from an 80/20 approach to the Easy Interval Method have been pleasantly surprised by smoother, faster running and an overall fitter feeling. Some who initially adopted the Norwegian approach, which includes several comparable sessions, also saw benefits as the Easy Interval Method proved to be lighter and more efficient. More than 40 testimonials located midway on this page stand as proof of these experiences.

Download a preview here (with a summary of what you can expect in the book + many reviews of enthusiastic readers) 

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Perform easy interval training instead of most of your endurance runs
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! Nearly all endurance runs are replaced by mostly relaxed interval training (think 'Zatopek'), which will benefit your high-end (as well as low-end) aerobic power and running economy. Easy interval training is the base of an EIM training schedule, instead of many endurance runs.

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 for 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.

- Read enthusiastic reviews at the bottom here 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 Streng

- Research by Belgium exercise physiologist Eline Lievens found that athletes with around 50-50% distribution of slow- and fast twitch fibers (can even be 30-70 or 40-60) need more recovery time compared to athletes with around 80-20% distribution. Click here for an article with a summary or here for the full report of the research. 
    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." 

The Easy Interval Method is ideally suited for this purpose, and as an added benefit, it can significantly improve your running economy. This is particularly advantageous for 'every-day' runners who frequently have an imbalanced ratio of slow runs to interval sessions.
Canadian runner Jonathan S: "The easy interval method is truly a gem. Forget the Vaporfly, this is the best thing any runner could buy. For real!"

About the author
The book Easy Interval Method was written by Klaas Lok, a 24-time Dutch national champion. He won titles over 1500m (3:38) up to 10,000m (28:24) and cross country and finished 2nd in the European Indoor Championships and 20th in the World Cross-Country Championships, both in 1980.

More about the book
    The book 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.

(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 )

Read on below the photo.



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) Faith Kipyegon 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 and 1 WR as a master 60-64.

Testimonials of top as well as 'every-day' runners:

- 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!" 

 
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!"

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."

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!" 

"A different approach"
"I like how its written, its 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 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!"

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. I feel like an aerobic monster".
In 2022, Andreas (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."

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." 

Martin Daniel 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."

"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. (Valencia Marathon 2023): "I finished my first marathon following the EIM principles so I want to share my experience and results using EIM for marathon training. Times of previous marathons with more conventional training: 3:30 - 3:13 and 3:03. This Sunday I ran my first sub-3 hour marathon at Valencia! (age 36). Very happy with my result!😃I really enjoyed the training and the marathon itself." 

Tom S. (Valencia Marathon 2023): "Another EIM marathon success story: 2.45.17, 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."

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!