David Poole, a Professor at Kansas State University specializing in oxygen transport and athletic performance, dives deep into the science of critical power and speed. He explains how these concepts serve as 'fatigue thresholds' in ultra-endurance training. The conversation includes the importance of tailored nutrition strategies, particularly the impact of low-carb, high-fat diets. Poole also addresses gastrointestinal challenges faced by ultramarathon runners and suggests innovative performance optimization techniques, including nitrate supplementation and specialized high-intensity training methods.