Terrain. Walking is usually on a finished, somewhat flat surface. Hiking - even in flat areas - generally have obstacles and uneven surfaces. Tree roots, branc

Terrain. Walking is usually on a finished, somewhat flat surface. Hiking - even in flat areas - generally have obstacles and uneven surfaces. Tree roots, branches with thorns, and so on. It isn't uncommon to do a bit of a climb either. If I'm in a good enough area, I might personally be crossing a stream on rocks. I'm guessing this has different output in the device: Steps taken hiking might not equal that on a walk, for instance, but may (in general) burn more calories.