For many years, the topic of whether a polarized or pyramidal training intensity distribution is more effective for endurance athletes has been hotly debated. Arturo Casado, PhD, is one of the foremost researchers in this area (and former European Champion in the 1500 metres). Today, Arturo dissects what the science really says in 2026: whether there is a winner, and if not, what are the athlete-specific, event-specific, and other variables that impact which training distribution will bring the best results. We also discuss specific training models from Canova to Norwegian from both scientific and practical perspectives, and bring it all together with practical advice relevant for amateur triathletes and runners.