This training plan produced impressive results when first published in 2014. Specifically, well-trained cyclists (and other endurance athletes) tested a 12% increase in VO2 max and an 8% improvement in power at 4 mmol/L after nine weeks of training in the classic study by Stöggl and Sperlich (1). Before we proceed to the specifics of the plan, let us revisit some pertinent "rules of engagement" that apply to all training advice: Always take individual circumstances into consideration when...