The document discusses new theories around fatigue and endurance training that challenge traditional models. It summarizes:
1) The central governor theory proposes that the brain regulates pacing and limits performance before catastrophic failure by anticipating fatigue based on feedback. This prevents buildup of metabolites and depletion of energy.
2) Evidence suggests muscle recruitment maxes out below maximum and brain activity dulls with training, indicating the brain regulates fatigue from the start of exercise.
3) The peripheral governor theory suggests regulation also occurs at the motor units to prevent failure, challenging the view that fatigue is solely centrally regulated.