Metabolic analysis during 7-day stage race examining fuel utilization patterns across days. Respiratory exchange ratio data shows progressive shift toward fat oxidation, with accompanying decrease in carbohydrate dependence. Athletes consuming >4000 kcal/day maintained better performance and body composition. Ketone production increased significantly after 48 hours, suggesting enhanced metabolic flexibility in adapted ultra-endurance athletes.
Tag: fat oxidation
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Long Run Training Adaptations in Marathon Preparation
Muscle biopsy analysis pre/post 16-week marathon training program examining cellular adaptations to long run training. Athletes performing weekly 20+ mile runs showed 34% increase in mitochondrial enzyme activity and improved fat oxidation rates. These adaptations correlate directly with marathon performance and ability to maintain pace in final 10K. Training runs at marathon pace + 10-30 seconds per mile optimize these adaptations.