Can information on remaining time modulate psychophysiological parameters during an intermittent exercise?

The purpose of the present study was to verify the effect of information on remaining time on physiological and perceptual responses during an intermittent exercise.

Ten trained cyclists participated in this study (176 ± 0.4 cm; 78.5 ± 10.4 kg; 32.5 ± 6 years; peak power output: 369.8 ± 37.8 W; VO(2peak): 51.90 ± 10.37 mL/kg/min). An intermittent cycling protocol consisting of four minutes at low-intensity (50% PPO) intervals followed by one-minute high-intensity bouts (100% PPO) under three different conditions were performed: OL40=40 min open-loop with no information on remaining time; CLI40=40 min closed-loop with information on remaining time; and CLI20=20 min closed-loop with information on remaining time. Ventilatory data (VO2) and electromyographic signals (EMG) were continuously recorded, and rating of perceived exertion (RPE) was acquired at the end of the high-intensity periods.

Results indicated that the oxygen consumption and muscle activity during OL40 were lower than CLI40. OL40 also demonstrated significantly lower VO₂values compared to CLI20 during high-intensity periods at 10 and 20 min. Root mean square values from EMG data for OL40 during high-intensity periods were significantly lower at 40 min compared with CLI40, and when the high-intensity period median frequencies among protocols were compared, CLI40 presented significantly higher values than the other conditions at 5 and 10 min.

Even when power output is maintained, information on remaining time may alter peripheral responses through a complex saving component to prevent higher energy expenditure during physical exercise.