Concept
Race prediction
An estimate that translates a recent race performance into a possible result at another distance.
How models work
Models such as the Riegel formula assume speed declines in a predictable way as race duration increases.
Why endurance matters
A prediction for a longer distance assumes the runner has trained the durability, fueling, and pacing needed for that distance.
Why uncertainty remains
Course, weather, execution, fatigue, and the quality of the source result can all shift the outcome.
How to use it
Use a recent well-executed race, choose a conservative target, and compare the estimate with specific training evidence.
Common misconception
A predicted time is not a promise or proof that the target pace is currently sustainable.