The Importance of Repetition in Interval Work

Brent Bookwalter: Every once in a while, it's really fun to go to failure with interval work. He said most of the time I want to leave something in the tank because I'm concerned about what I need to do next day. Renato Konnavad has coached all the Kenyans and he says they can fly on an interval session if they're having fun. "It doesn't have to be a disaster when our athlete goes off the reservation a little bit"