Race splits
| Distance | Split | Total time |
|---|
Splits assume an even average pace from start to finish. On a real course you will be slower on the climbs and faster on the descents, so treat them as a guide.
How the elevation adjustment works
The calculator uses the running energy cost equation from Minetti et al. (2002), which gives the energy cost of running one metre per kilogram of body mass at a gradient i (rise divided by distance, so 0.08 is an 8% slope):
Cr = 155.4i⁵ − 30.4i⁴ − 43.3i³ + 46.3i² + 19.5i + 3.6 (J/kg/m)
Flat running costs 3.6. Climbing costs more, and gentle descents cost less, with the lowest cost at around a 10% downhill. Your ascent and descent are turned into climbing and descending sections at the steepness you chose, the rest of the course is treated as flat, and the total energy cost is compared with running the same distance on the flat. That ratio gives the flat-equivalent pace and the finish time.
This is an estimate. It assumes steady effort, runnable ground and climbs and descents spread evenly along the course. In practice, steep climbs are often walked, technical descents slow you down, and fatigue builds over long distances, so treat the result as a guide rather than a promise.
Source: Minetti AE, Moia C, Roi GS, Susta D, Ferretti G. Energy cost of walking and running at extreme uphill and downhill slopes. Journal of Applied Physiology 93: 1039 to 1046, 2002.