Jack Daniels (born 1933) was a professor of physical education and cross-country running coach at State University of New York at Cortland. He received his doctoral degree in exercise physiology at the University of Wisconsin-Madison. Named “The World’s Best Coach” by Runner's World magazine, he led Cortland runners to eight NCAA Division III National Championships, 31 individual national titles, and more than 130 All-America awards. He is famous for writing Daniels' Running Formula, a 1998 book detailing his unique training philosophies. Dr. Daniels resides in Flagstaff, Arizona where he mentors and coaches some of America's top distance runners.

Daniels defines the value VDOT to measure a runner's ability to run fast. The VDOT value is calculated based on a runner's result in a recent competition. Factors like mental toughness and running economy are taken into account, as opposed to for example V02max, which only measure one factor in laboratory tests. Daniels concludes that VDOT is, due to this holistic view, a better value to assess fitness from.

Daniels divide running performance into six components. Daniels argue that each of these components require a specific training intensity to improve.