The Eddington number in the context of cycling or running is defined as the maximum number E such that the athlete has covered at least E km on at least E days.

For example, an Eddington number of 70 would imply that a cyclist has cycled at least 70 km or miles in a day on at least 70 occasions. Achieving a high Eddington number is difficult, since moving from, say, 70 to 75 will (probably) require more than five new long-distance workouts, since any workout shorter than 75 km or miles will no longer be included in the reckoning.