Physiological and Perceptual Responses During 4-Second Exercise

The Effects of The Exercise Intensity and Rest Duration on Physiological and Perceptual Responses During 4-Second Sprint Interval Exercise

The purpose of this study is to investigate the acute effects of different intensities (i.e., 50, 75, and 100% of maximal anaerobic power) of 4-s sprint interval exercise on physiological responses. Secondly, it will determine the relationship between intensity and recovery duration (i.e., 15, 30, or 45-s) that will stimulate the cardiovascular and metabolic systems.

Background Short sprint interval training (sSIT) is typically performed at maximal intensity, generating power far above what is needed to reach peak oxygen consumption (VO₂peak). However, the physiological effects of submaximal sprint intensities and different recovery periods are not well understood.

Study Aim This study examined how power output and oxygen consumption (VO₂) respond to repeated 4-second sprints at 50%, 75%, and 100% of maximal power (Pmax) with rest periods of 15, 30, or 45 seconds.

Methods Eleven recreationally active participants completed nine trials, each consisting of thirty 4-second cycling sprints under different intensity and recovery conditions.

Inclusion Criteria:

• Young (18-30),
• Healthy,
• Recreationally active, but untrained (not meeting ACSM's recommendations of 150 min/week of moderate-vigorous aerobic exercise)

Exclusion Criteria:

• Cardiovascular disease
• Smoking
• Subjects who were exercising regularly (>75 min/week) were excluded.