To succeed in a marathon using Pfitzinger-style plans, the community suggests aiming for Goal Marathon Pace during long runs, while accepting flexibility based on actual fatigue, weather conditions, or current fitness.

noli's read

The consensus among runners is that these sessions are extremely demanding and often perceived as a partial failure if the pace is not maintained, even though final success on race day remains frequent. Scientifically, the principle of threshold or specific-pace training is validated by studies (e.g., Casado et al., 2022, review on periodization) that highlight the importance of specificity to acclimate the body to metabolic stress; however, training based on heart rate or perceived exertion is often preferred in the literature to avoid overtraining. It is widely accepted that heat and humidity management alters the physiological response, making pace adjustment (rather than blind adherence to a target) more effective for avoiding injury or exhaustion. The idea that one can miss these preparation sessions while still succeeding in the race thanks to the taper is an empirical phenomenon well-documented in long-distance running plans. The community is divided between disciplinary rigor and pragmatic adjustment according to daily fitness, signaling a nuanced approach rather than a strict dogma.

the sources

1. 1r/AdvancedRunning