The Accumulation of Performance Fatigue and Perceptual Responses across Consecutive High-Intensity Interval and...

Area of Science:

• Exercise Physiology
• Sports Science
• Human Performance

Background:

• Understanding the impact of repeated exercise sessions within 24 hours is crucial for athletes and occupational settings.
• Performance and perceptual responses to consecutive high-intensity interval training (HIIT) and constant-work rate (CWR) cycling are not well-established.

Purpose of the Study:

• To investigate the effects of repeated, consecutive HIIT and CWR cycling sessions on performance fatigue and perceptual responses within a 24-hour period.

Main Methods:

• Seventeen healthy adults completed three cycling sessions (morning, afternoon, next morning) of matched HIIT and CWR protocols.
• Neuromuscular function (maximal voluntary contraction, superimposed and potentiated twitches) and time-to-task failure (TTF) were assessed.
• Blood lactate and perceptual responses (e.g., perceived effort, dyspnea) were also measured.

Main Results:

• Time-to-task failure (TTF) was longer after CWR compared to HIIT.
• Consecutive sessions led to progressive impairments in cycling TTF following CWR, associated with depressed voluntary activation.
• Maximal voluntary contraction and evoked twitches returned to baseline before each session, but perceived effort and dyspnea were higher in HIIT.

Conclusions:

• While maximal force-generating capacity recovered, consecutive exercise sessions can compromise the recovery of voluntary activation.
• Endurance performance, specifically time-to-task failure, may be impaired following repeated exercise bouts within 24 hours.