Trail pacing — total time with elevation gain/loss

Estimate total time of a trail run knowing distance, elevation gain, elevation loss and your flat pace. Uses Minetti et al. 2002 energy cost of running on slopes. The 'GAP' is your grade-adjusted pace.

Assumes roughly even distribution of climbs and descents. Real trails with one long climb followed by one descent behave similarly. Highly fragmented profiles vary more.