What is Interval Training?

What is Interval Training?


‘Original Interval Training’ 

The origins of Interval training typically date back to the 1930’s and a man called Dr. Woldemar Gerschler, a German coach who teamed up with a physiologist called Dr. Herbert Reindel. The applied Gerschler’s understanding of the importance of cardiovascular conditioning in the search for a training method which would maximise the size, fitness and efficiency of the heart. To cut a long story short, Gerschler invented a type of repetition training using shorter reps of 200m-400m with a recovery break between each repetition allowing the heart rate drop back to 120 beats or so. The name of the system, ‘Interval Training’, reflected the rest of recovery period between the faster runs, considered the most important and vital part of training. It is during the interval that the heart adapts, growing larger and stronger.

Sample 1:  8-10 x 400m @ 3000m race pace with 60-90 seconds walk or jog recovery between reps

Sample 2: 12-16 x 400m @ 5000m race pace with 45-60 seconds walk or jog recovery between reps

Sample 3: 8-10 X 1000m @ 10000m race pace with 60-90 seconds walk of jog recovery between reps

‘ New’ Interval Training

Move on to the present and many athletes/coaches continues to use interval training in many forms. Peter Thompson a UK coach has developed a system called ‘New Interval Training’ which is simply any repetition training where the training effect takes place during recovery intervals between the faster paced runs. What the athletes does in the interval between the faster repetitions when using the “New Interval Training” is an active ‘roll-on’ running recovery.

Sample 1: 2 sets of (4-5 x 400m @ 3000m race pace) with 200m roll on jog recovery in 60 seconds & 3 min easy jog recovery between sets

Sample 2: 3-4 sets of (4 x 400m @ 5000m race pace) with 100m roll on jog recovery in 30 seconds & 3 mins easy jog recovery between sets.

Sample 3: 2 sets of (4-5 x 1000m @ 10000m race pace) with 400m roll on recovery in 2 minutes and 3 mins easy jog recovery between sets

Fartlek Training

Fartlek training is another form of training used by athletes and coaches with great success. This type of training was said to have been developed by Swedish coach Gosta Holmer and the word ‘fartlek’ itself comes from the Swedish ‘speed play’. This is an aerobic-type training which provides a variety of speeds and paces. This type of training allows athletes to run whatever distance and speeds they wish and to play around with the recoveries. Fartlek can be done almost anywhere, including forests, on rolling terrain, on trails, on grass pitches etc. These are always done in control, at paces roughly from marathon to 5K, at an RPE of roughly 6-7/10 and always in the best technical running model

Sample 1: 2-4 sets of 30/45/60/75/90/75/60/45/30 seconds with EQUAL easy walk/jog recovery after each repetition and 3 mins easy walk/jog recovery between sets

Sample 2: 2-4 sets of (3/2/1 minutes) with HALF the rep easy walk/ jog recovery between repetitions and 3 easy walk/jog between sets

Sample 3: 2-3 sets of (30 secs/4 mins/30 secs/3 mins/30 secs/ 2 min/30 secs/1 min) with EQUAL jog recovery on the 30 sec reps & HALF the rep jog recovery on longer reps.

Hill Intervals

Hill training can provide a great training stimulus for all levels of runners and for all race distances. They provide a number of benefits including aerobic conditioning, providing an anaerobic stimulus, increasing leg strength, increasing power output, improving running mechanics, improving running economy, providing a neuromuscular stimulus, develops coordination,enhances strength endurance, develops speed, etc. There are many forms of hills that can help endurance runners but some factors take into account before deciding what type to use are;

  • Target Race Distance
  • Individual Athlete Profile
  • Stage of Season
  • Proximity to Key races
  • The training that came the day before and comes the day after

Sample 1: (Aerobic Hills)- 3 sets of (4 X 60 secs) with easy jog back down recovery after each repetition and 3 mins easy jog or walk between sets.

Sample 2: (Short Power Hills)- 6-8 X 10 seconds MAX Effort Sprints on a STEEP incline with a full 3 mins walk recovery after each one

Sample 3: (Mixed Hills)- 2-4 sets of (2 X 60 secs Aerobic Hills (jog back down recovery) into 2 X 20 secs Short Power Hills (walk back recovery) and 5 mins/jog between sets

Blend Interval Workouts

These are developed by US coach Steve Magness in his book “The Science of Running” and specifically for track athletes. Essentially it is about brining two different intensities together and connecting them. They are useful way of bringing speed and endurance parts together. The changes of paces during the workout causes the following physiological events:

  • Muscle fibre recruitment and lactate levels are constantly changes ( on faster parts more fibres are recruited and more lactate is produced. On slower parts the runner has to deal with the higher lactate levels
  • Muscle fibre that are recruited during the faster rep, likely extended their endurance during the slower portion

Sample 1: 1000m (5km pace), 400m (1500m pace), 800 (5km pace), 300m (1500m pace), 600m (5km pace), 200m (1500m pace), all with 3 minutes walk/jog recovery

Sample 2: 1600m (10km pace), 600m (5km pace), 1600m (10km pace), 400m (3km pace), 1600, (10km pace), 400m (3km pace), 1600m (10km pace) all with 2-3 minutes walk/jog recovery

Sample 3: 4 Miles (Marathon Pace), 1 MIle (LT), 4 MIles (MP), 1 Mile (10km pace) all with 3 minutes walk/jog recovery


There are many forms of interval training available to athletes and a simple rule of thumb would be to use all forms over a training block and continue a vary pace, terrain and surfaces. When starting any type of interval training, gradually introduce this to your program and add more tome depending on how your body responds to the training. When using interval training think about the following:

  • Choosing the correct pace
  • Choosing the correct length of interval
  • Choosing the correct recovery interval
  • Choosing the total volume of workout

When you change any of the variables above you change the stress involved in the workout. We know that in order for an athlete to become fitter we must apply a stimulus and allow them to adapt. By running faster, increasing the length of the interval, reducing the recovery, increasing total volume of he workout etc we are increasing the stress involved with the workout.  Be creative with this part and don’t feel that ‘one size fits all’; it doesn’t

Finally all types of interval training are only beneficial when you have laid a solid aerobic foundation first through easy aerobic foundation first through easy aerobic running, long runs, tempo/threshold runs, strength and conditioning exercises, drills, strides etc. When the aerobic foundation has been laid, an athlete becomes more robust, can handle more volume and intensity of training and will gain more from the interval training. This aerobic work must also be  continued or maintained during the interval training period

For most athletes small doses of interval training are all that is needed to produce a good race performance. Too much can have a negative impact-especially when done too intensely. Intervals are not only for speed and anaerobic development; they can be used for aerobic development. It’s all about balance!

All the training examples above are just samples and must always be applied to the individual athlete correctly according to their exercise history, running background, injury, history etc

By Steven Macklin