Interval training is based on the principle that shorter, high-intensity workouts are more effective than longer, less-intense sessions. During interval training sessions for runners, the athletes alternate maximum- or near maximum-intensity sprints with recovery intervals during which they walk or jog. Even though the training involves sprints, interval workouts are popular among distance runners as well, as they build stamina and burn excess fat.
In the track and field world, interval training was popularized in the 1940s and ‘50s by Emil Zatopek, who won two Olympic gold medals at 10,000 meters and one each at 5000 and the marathon. Zatopek’s training was legendarily brutal, as he reportedly alternated 400-meter sprints with 200-meter jogs during four-hour workouts. But you’ll find almost as many ways of performing interval workouts as you’ll find coaches who direct their runners to perform interval training.
Short sprinters, as you’d expect, tend to run shorter distances during interval training sessions – 50 to 60 meters on a track, or up a hill, for example – followed by three- to five-minute recovery walks. Longer sprinters might do 100-meter repeats followed by recovery intervals, while distance runners may go 400 to 600 meters, or even longer, during the high-intensity phases – although obviously not at the type of intensity a short sprinter would maintain for 50 meters.
Fartlek training is an offshoot of the interval workout, without the strict structure. Where an interval session may consist of eight 50-meter sprints, each followed by a four-minute walk, in Fartlek training you typically run hard for a while and then slow down – but don’t stop – whenever you wish, before you decide to pick up the tempo again. Fartlek means “speed play” in Sweden, where the technique was pioneered in the 1930s and eventually picked up by Gunder Hagg, who set 15 world records at distances of 1500 to 5000 meters.
The 10-20-30 Method
More recently, Danish researchers Thomas Gunnarsson and Jens Bangsbo developed the 10-20-30 interval approach. To use their method, divide your training session into one-minute segments. Run the first 30 seconds at 30 percent of your maximum intensity, the next 20 seconds at 60 percent intensity and the final 10 seconds with 90 percent of your maximum effort. Repeat the pattern four more times without rest, for a total of five, one-minute segments. Rest for two minutes and then do two or three more five-minute sets.
In 2012 study, Gunnarsson and Bangsbo recruited 10 “moderately trained” men and women who performed 10-20-30 interval training three times per week for seven weeks. The runners did the interval workouts in place of their normal routines. As a result, the subjects trained for about half their normal time. Nevertheless, the runners improved their 1500-meter times by an average of 21 seconds and their 5000-meter performances by 48 seconds. These times represented improvements of 6 and 4 percent, respectively, in the two events, within seven weeks. The study’s results were published in the Journal of Applied Physiology in July 2012.
Be Careful Out There
Interval training is intense and carries a greater injury risk than steady-state endurance running. If you’re part of a track team, have your coach supervise your training. If you’re working on your own, consult your doctor before you try interval training, then take it relatively slow to begin. Don’t venture to close to 100 percent effort during the high-intensity phases, and include generous recovery periods. You can increase the intensity and shorten the recovery periods gradually as you adapt to the training.
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