Should You Run More Miles?

New Zealand coach Arthur Lydiard, who passed away in 2005, was most well known for his high-mileage approach. Even his middle-distance runners ran 100 miles per week, like Peter Snell, who won gold medals in the 800 and 1500 meters at the 1960 Olympics. But is that amount of mileage necessary? Was Lydiard right, or did his talented athletes run well despite their training rather than because of it?