A group led by Professor Yasuo Kawakami of Waseda University's Faculty of Sport Science and Researcher Takuki Yamagishi of the National Sports Science Center has found that high-intensity intermittent exercise of just 40 seconds can improve oxygen consumption (aerobic energy metabolism) in the whole body and muscles. It was also found that the activity of the major muscle groups in the thighs can be sufficiently increased.
The WHO guidelines recommend ``at least 150 minutes of aerobic exercise a week'' and ``strength training at least twice a week'' to promote health and prevent disease, but exercise is easy to do in today's busy society. Probably not. Therefore, in recent years, research on the ``minimum amount'' that produces training effects has been gaining momentum.
What is attracting attention is high-intensity intermittent exercise, which is ``concentrated and repeated at a high intensity for a short period of time''. However, the optimal solution (intensity, duration, number of repetitions) of high-intensity intermittent exercise and its effects on muscles were unknown.
Therefore, in this study, we performed different high-intensity intermittent exercises to examine the whole body and muscle oxygen consumption (energy metabolism) and thigh muscle activity from multiple angles. As a result, the following was revealed.
1. When repeating all-out sprints for 10 seconds or longer, two sprints are sufficient, as the increase in oxygen consumption of the whole body and muscles reaches a plateau after the second sprint.
2. Muscle oxygen consumption is greater in a 10-second sprint than in a 20-second sprint.
3. Just 40 seconds of high-intensity intermittent exercise (two 20-second sprints) significantly increases activation of key muscle groups in the thighs.
From the above results, it was found that even a short training session can have a large exercise effect by adjusting the intensity. By regularly performing this exercise (20 seconds x 2 full-power sprints) once or twice a week, you can improve your maximum oxygen intake, which is an indicator of whole body endurance, and your thigh muscle mass. It is expected that muscle strength will improve.
The results of this research are expected to contribute to the development of efficient training for athletes and to improving the rate of exercise implementation around the world.
