Development of High-Intensity Interval Training: Towards the minimal dose of high-intensity interval training for inducing various physiological and performance adaptations.

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K19990
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59020:Sports sciences-related
• Research Institution: National Agency for the Advancement of Sports and Health (2021-2022); Waseda University (2019-2020)
• Principal Investigator: Yamagishi Takaki 独立行政法人日本スポーツ振興センター国立スポーツ科学センター, スポーツ科学・研究部, 契約研究員 (10794696)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 間欠的高強度運動 / スプリント時間・本数と生理学的応答の関係性

Outline of Final Research Achievements

This research project aimed to determine the dose-response relationship of sprint and physiological responses at whole-body and peripheral levels. It has been shown that only 30 s of all-out sprints (2 sets of 15-s sprint) significantly increased pulmonary oxygen uptake and oxygen extraction at vastus lateralis and rectus femoris. Furthermore, significant increases in the recruitment of thigh muscles were also confirmed with two 15-s all-out sprints by functional magnetic resonance imaging. In addition, this study also showed that there was a blunted response of oxidative metabolism (as determined by pulmonary oxygen uptake and tissue oxygenation index at thigh muscles) with sprint repetitions, that is, no further increases in those parameters when all-out sprints (>10s) were repeated two to three times. The current results would explain previous research findings that showed increases in sprint repetitions do not necessarily augment physiological adaptations (maximal oxygen uptake).

Free Research Field

スポーツ・運動生理学

Academic Significance and Societal Importance of the Research Achievements

先行研究によりスプリントの時間や実施本数を一定程度減少させてもトレーニング適応が損なわれないことが示されていたが、その生理学的機序については知見が限られていた。本研究により、10秒以上のスプリントを反復した際に全身・局所のエネルギー代謝の増大が2セット目以降は鈍化することを明らかにし、先行研究の知見を裏付けたことは学術的意義が高いといえる。さらに、本研究は僅か計30秒（2x15秒）のスプリントが有酸素性エネルギー代謝および下肢筋群の代謝応答の増大をもたらすことを示した。運動実施の障壁として「運動時間の確保」は最も頻繁に挙げられる理由だが、本研究の成果は現代人の運動参加を促す一助となり得る。