ABSTRACT
AIM: 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. METHODS: 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: 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. CONCLUSION: 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.
