Physiological aspects and energetic contribution in 20s:10s high-intensity interval exercise at different intensities

Area of Science:

• Exercise Physiology
• High-Intensity Interval Training (HIIT)

Background:

• The Tabata Protocol is a popular high-intensity interval exercise, but its physiological demands and energy contributions are not well understood.
• Previous studies lacked detailed descriptions of work intensity, potentially due to protocol feasibility issues.

Purpose of the Study:

• To investigate the physiological demands and energetic contributions of the Tabata Protocol at varying intensities.
• To clarify the differences in physiological responses between physically active students and well-trained athletes during this exercise.

Main Methods:

• Eight physically active students and eight trained cyclists performed interval training (20s:10s work:rest) at 115%, 130%, and 170% of peak power output (PPO).
• Measurements included sprints, power output, oxygen consumption, blood lactate, and heart rate.
• Data were analyzed for differences between groups and intensities.

Main Results:

• Significant differences were found between exercise intensities regarding sprints, power output, blood lactate, and heart rate.
• The aerobic system was the predominant energy contributor across all intensities.
• Higher aerobic contribution occurred at 115% PPO, while the alactic system contributed more at 130% PPO.

Conclusions:

• The aerobic system is the primary energy source during the Tabata Protocol, even at high intensities.
• Energy system contribution varies with exercise intensity, with lower intensities favoring aerobic contribution and higher intensities favoring anaerobic systems.