How we measure

Hills, and what they cost

A kilometre is not a kilometre. Nine kilometres up a mountain can cost more than twenty on the flat, so distances and paces on Livebib can also be shown hill-adjusted: what the same effort would come to on level ground.

Two ways up the same mountain

Kebnekaise has a western route of 9.1 km with 1,536 m of climb, and an eastern route of 7.3 km with 1,372 m. In kilometres they look close. Hill-adjusted, the western route is 20.4 km and the eastern one 16.9 km, so the shorter route is also the smaller day, by a sixth. That is the question kilometres cannot answer, and the reason we show both numbers.

Where the numbers come from

The cost of a slope comes from Minetti et al. (2002), a laboratory study of the energy cost of walking and running on extreme uphill and downhill slopes. We normalise it so level ground is exactly 1.0, then add the cost up metre by metre along the route. A gentle descent comes out cheaper than flat ground, which surprises people, and is the most economical running there is.

What it does not know

The curve was measured on running without a pack, so a hiker carrying twelve kilos will find it optimistic. It models the slope and nothing else: not rock, not mud, not snow, not altitude, not heat. Slopes beyond 45 per cent are capped rather than extrapolated. Read it as a fair comparison between two routes, not as a promise about your day.

It is an estimate, and it says so

Anything Livebib has calculated rather than recorded is shown in amber. Green means measured: a real position at a real time. Amber means our best estimate. Hill-adjusted numbers are always amber.