The exercises included simple calisthenics such as running in place, modified burpees and squat jumps.
Participants performed the activities at a self-selected "challenging" pace, interspersed with light active recovery periods.
The 11-minute routine, which included a brief warm-up, does not demand extraordinarily high levels of motivation or "all out" efforts, which are common to many intense interval training approaches.
After six weeks of training, three times per week, cardiorespiratory fitness was higher than in a control group that did not exercise.
