In 2009, the International Conference on “Strength and Conditioning” was held in Zagreb and the main topic was endurance training. Among many lectures presented, I was especially looking forward to one on fartlek and interval training. Such types of training are not new, but discussing acute and chronic effects on performance always sparks big interest.

Here we will explain the difference between fartlek and interval training, their basic characteristics and application in sport and recreation.


Fartlek is the type of training done on even or uneven terrain where intervals of running at different pace and duration is combined.

It was born in the thirties of the last century as a “Swedish school’s” reaction to the Finnish “repeating method” that was abundantly used by Finnish legendary runners Paavo Nurmi, Ville Ritola and Juho Hannes Kolehmainen.

Name comes from the word “fara” which in old Norwegian means “to go, to move” and “leika” which means “to play”. Consequently, the literal translation of the term would be “a speed game”.

Gustaf Richard Mikael Holmer (Swedish decathloner, coach, winner of bronze medals at OI in Stockholm in 1912) was the first who introduced this type of training. If you try googling it, you may stumble upon problems since it can be found under various names like:

  • Continuous method
  • Interval method
  • Combined method
  • Specific method
  • Self-reliant method

Holmer wrote that there are few advantages of fartlek training:

  1. Running on uneven terrain, sand, snow, hilly terrain, where the ground is elastic, 1-2 hours per day, excellent tool for the cardiovascular and locomotion apparatus
  2. Helps developing runner’s self-confidence
  3. It can be used in sports such as: athletics, sports games, martial arts and all sports with the competitive activity of varying character
  4. Achieves performance effects at all stages of the training process.

The first example of such a training is somewhat different than those we use today but it looked like this:

  1. Warm up: slow run for 5-10 minutes
  2. Fast run 1.5-2 km
  3. Resistance: fast walk about 5 min
  4. Start of speeding activities: easy running with intermittent sprints of 50-60 m long, repeated to light fatigue
  5. Easy run with multiple repetitions of 3-4 explosive steps
  6. Maximum fast running uphill 170-200 m
  7. Fast steps 1 min
  8. Repeat the complete program until the end of the scheduled training time

As can be seen from the enclosed, fartlek has features of continuous training interspersed with different intervals. At first glance it seems that the training program is unprogrammed, unsystematic and depends largely on the configuration of the terrain, but in reality it is fun and perfect for small groups where everyone can lead 1 or 2 intervals without worrying about pace of running.

Example of fartlek done on treadmill:

  1. warm-up 5 min at speed of 5-6 km / h slope 8.0% (hold the treadmil and spend 1 min walking on the toes, then heels, then 2 min of normal walking)
  2. Run 10 min at speed of 10.0 km / h
  3. Run 15 min (1 min speed 12 km / h slope 4.0% with 2 min run speed 10.0 km / h, drop 1.0%)
  4. Run 10 min (1 min speed 14.0 km / h, 2 min speed 5.0 km / h and stay at 1.0% all the time)
  5. Cool down: run 10 min (speed 9.0, slope 0.0%)

In this training you will see the following features:

  1. Energy consumption is higher than with continuous methods
  2. It is Ideal for early preparatory phase (getting the base & mileage)
  3. Less stressful than interval training methods for the locomotor system
  4. Due to its flexibility it easily adapts to all sports and training goals
  5. The disadvantage is non-standardization and difficulty in verifying it scientifically
  6. Increases the attractiveness of training itself, reduces monotony

Fartlek is present in more and more training programs that promote large companies specialized in sales and marketing of sports equipment. For example, Nike has combined music of different tempo with Nike + that can guide a runner during his fartlek. A similar project was made by Adidas AG with its MyCoach.

Joining music and training was shown as a winning combination, and the kind of training used in their programs is fartlek.


The interval training method developed between the two world wars, while it became very popular in the 1960s after Thomas H. Reindell, H. Roskamm and W. Gerschler published a book called Das Interval training. This masterpiece kept secrets of over 15 years of research done on more than 4000 athletes.

At the very beginning, the theoretical setting of this type of training included load intervals and rest intervals. The ratio between work and rest was 1: 2 or 1: 3. The interval required a work of approx. 180 beats/min for 30 seconds, after which there is an interval of rest that is 2-3 times longer than the work interval or until the heart rate drops to 120 beats/min.

In this method of training, resting days have been introduced as an integral part of training. That novelty helped in developing methods of recovery that were by then relatively unknown.

Today there are numerous variations of interval training and they can be used in almost every sport. One of the most famous variations of the interval training is HIIT (High Intensity Interval Training). Many today’s popular training routines like Tabata etc. are based on such programs.

Interval Training characteristics:

  1. Balance between working and resting intervals
  2. The relationship between work and rest is 1:2; 1:3.
  3. It is extremely stressful for the locomotor and cardiovascular system
  4. It is recommended in the central and late stage of sports preparation and for experienced recreational athletes.
  5. Not recommended for working with children
  6. Carbohydrate is primarily used as an energy source – nutrition is essential before and after such training
  7. Applies to almost all sports activities

Example of interval training on treadmill:

  • 10 min warm-up (running 10.0 km/h, slope 1.0%)
  • Dynamic stretching of the entire body
  • Run: 45 sec (speed 15.0 km / h, slope 1.0%)
  • 120 sec rest intervals (breathing exercises or stretching activated musculature)
  • Repeat 4-6 times

This training is only arbitrary and is suitable for experienced athlete. For achieving wanted results, consult a trainer who will be able to test your skills and tailor training program just for you.

After a very intense work, the cooling of the organism is an imperative. Spend 10-15 minutes on one of the ergometers (I recommend the bike) and cycle around 60% of the maximum heart rate. Then you can stretch to decrease muscle stiffness.

Acute microfractures of muscle tissue and structural damage have probably occurred, especially if you feel DOMS (Delayed Onset of Muscle Soreness) or delayed muscular pain that occurs 24-48 hours after training. Long-term exposure to this type of training, while neglecting the recovery leads to poor adaptation and gradually to losing or just maintaining moderate relative muscle strength.

Particular attention should be paid to strengthening of antagonistic and synergistic muscle groups. Otherwise, there is a disbalance of musculature that can lead to overuse or injury (acute and chronic).

How to Determine Which Training Type Is For You?

Fartlek is certainly a great method of training for beginners or for athletes in the initial stage of preparation. It is good for locomotor system, easily adjustable for current level of fitness and tailored for running outdoors on various surfaces.

The intermittent method is extremely stressful, but it gives better results. It is not recommended using it often in younger age groups since muscle damage is significant. It is used by athletes in the final stage of sports training, as well as the experienced recreational gym ent