Lydiard learned that no matter how tired he was from recent training, he could almost always manage to run again if he kept the pace slow. But he did not always run slowly. Lydiard played around with the intensity of his running almost as much as he did with the volume. These investigations taught him that speed work helped the most when it was sprinkled lightly on top of a huge foundation of slow running. In essence, he invented 80/20 training.
