The original protocol set a 2:1 ratio of work to recovery periods, for example, 30--40 seconds of hard sprinting alternated with 15--20 seconds of jogging or walking.
The original protocol set a 2:1 ratio of work to recovery periods. This was for example. Example was 30--40 seconds of hard sprinting--20 seconds of jogging or walking. This hard sprinting was alternated with 15.