In the 1960s, New Zealand athletes took the Olympics by storm. They won medals from 800 meters to the marathon and what was most shocking was that the medalists were all from the same town with the same coach. Naturally, everyone wanted to know all about their training.
The coach, Arthur Lydiard, was only too happy to share. Lydiard believed (after experimenting on himself) that if you prefaced interval training with running to build your aerobic system (and followed this with hill training to build strong, dynamic legs), you could improve performance in the interval training phase of training. This would allow you to race faster and most importantly, would allow you to peak on time (which his athletes became famous for).