Fartlek, or Interval Training : Fartlek comes from Swedish meaning “speedplay”.
Interval training is a method of training where you alternate between high and low intensities during your workout with the objective of increasing your stamina and speed.
In this example, the work:active-recovery ratio is 1:3
1. Jog for five minutes to warm up.
2. Increase the speed to about 70% of your maximum and run at this pace for one minute.
3. Slow down and jog for three minutes.
4. Increase the speed again and run for one minute.
5. Jog for three minutes.
6. Repeat these intervals for your entire workout (about 30mins max depending on age and ability)
7. Jog to warm down afterwards and don’t forget to stretch.
As you improve -increase the work = speed component and decrease the recovery component.
After a couple of months you will find you can run at a faster speed for longer.