Physiological differences between cycling and running: lessons from triathletes

Area of Science:

• Exercise Physiology
• Sports Science
• Biomechanics

Background:

• Physiological responses to exercise vary significantly between different modalities like cycling and running.
• Understanding these differences is crucial for optimizing training and performance in athletes, particularly triathletes.

Purpose of the Study:

• To review and synthesize existing literature on the physiological distinctions between cycling and running.
• To compare key physiological variables and explore the underlying mechanisms of adaptation to each exercise modality.

Main Methods:

• Comparative literature review of studies measuring maximal oxygen consumption (V O(2max)), anaerobic threshold (AT), heart rate, and efficiency.
• Analysis of physiological variables in cyclists, runners, and triathletes across different exercise intensities.
• Examination of underlying mechanisms including ventilatory responses, blood flow, muscle oxidative capacity, and neuromuscular fatigue.

Main Results:

• Maximal oxygen consumption (V O(2max)) is modality-specific; runners typically show higher values during running than cyclists during cycling, though cyclists can achieve similar V O(2max) values on a cycle ergometer.
• Muscles demonstrate specific adaptations to exercise tasks, improving submaximal variables like ventilatory threshold, potentially more so in cycling.
• Physiological training transfer is likely greater from running to cycling than vice versa; heart rate, delta efficiency, and ventilation also differ between the two activities.

Conclusions:

• Exercise modality significantly influences physiological adaptations and performance metrics.
• While V O(2max) is largely specific to the exercise, submaximal adaptations and training transfer show distinct patterns between cycling and running.
• Further research is needed to fully elucidate the mechanisms behind V O(2max) and AT differences, considering factors like cardiac output, muscle mass recruitment, and oxidative capacity.