Stop running your easy days too hard and your hard days too easy. Targeted at highly experienced athletes pushing their absolute physiological limits, this 20-week plan introduces elite two-a-day training stress. By pairing primary hard intervals and moderate-threshold runs with secondary cross-training sessions (FRB30), we maximize mitochondrial density and lactate-clearance capacity. This is a high-frequency, high-volume protocol for the athlete who demands the highest possible half-marathon ...