Peripheral and central inputs to the effort sense during cycling exercise

Area of Science:

• Exercise Physiology
• Human Performance
• Sports Science

Background:

• Perceived effort is a crucial factor in exercise adherence and performance.
• Understanding the interplay between physiological responses and subjective effort perception is vital for optimizing training protocols.

Purpose of the Study:

• To investigate the relationship between physical and physiological factors and perceived effort at different pedaling rates.
• To explore how exercise duration influences the perception of effort at equivalent work outputs.

Main Methods:

• Subjects performed a 4-minute exercise bout at various work outputs and two pedaling rates (30 and 60 revolutions per minute).
• Physiological measures including ventilation (VE), oxygen consumption (VO2), and integrated electromyography (IEMG) were recorded.
• Subjects continuously judged their perceived effort throughout the exercise duration.

Main Results:

• At equivalent work outputs, pedaling at 30 rpm was perceived as more effortful after 4 minutes, despite similar VE, VO2, and IEMG-min-1 compared to 60 rpm.
• Effort perception correlated with VO2 and IEMG-min-1, but the pedaling rate significantly influenced effort after prolonged exercise.
• Initially (15 seconds), pedaling rate had minimal effect on effort relative to resistance, but this effect grew with exercise duration, suggesting a central signaling component.

Conclusions:

• Perceived effort during cycling is influenced by both peripheral physiological signals and central factors, particularly over time.
• The pedaling rate's impact on perceived effort intensifies with exercise duration, potentially mediated by central motor commands.
• A model integrating peripheral and central signals is proposed to explain the sense of effort during exercise.