We know the 10-20-30 interval technique works to improve performance, but the most fascinating finding from the new research is that those final 10 seconds don’t need to be as intense as you might think.

To reach this conclusion, the researchers recruited 19 runners and asked them to replace their normal training with 10-20-30 sessions. Each of these sessions involve three to four 5-minute blocks with recovery periods in-between; the participants took part in three of these sessions every week over the course of six weeks.

However, there were some differences between what these runners were asked to do. While half of the group stuck to the usual 10-20-30 approach – running at 100% intensity for those final 10 seconds – the second half were asked to hold themselves back a bit on the final section, only using 80% of their maximum effort.

The researchers recorded the 5k times of the runners both before and after the six weeks of training and found that those in the 80% group achieved an average improvement of 42 seconds, compared to a 24-second improvement recorded in the 100% group. Both groups saw an average VO2 max improvement of 7%.

Want to run faster? Research says the 10-20-30 technique is the key