A route is just a line until you know what it climbs. Here's why the profile matters more than the distance.

Distance lies

A flat 10k and a 10k with 400m of vert are two different sports. The number on the poster doesn't tell you which one you signed up for.

Read the shape

The profile tells you where the climb starts, how long it holds, and what you'll have left for the descent. That's the whole race, drawn in one line.

Respect the vert

Add ten percent to your time for every hundred meters of climb. It's not exact, but it keeps you honest.