How Terrain Affects Calorie Burn While Rucking
Different surfaces change your energy expenditure by 10-100%. Here's what the science says about terrain coefficients and why Hiko tracks 9 terrain types.
Walking on sand burns nearly twice the calories of walking on pavement at the same speed. This is not a guess — it is a measurable physical cost that the military has studied since the 1970s.
Why Terrain Matters
Every surface you walk on creates a different amount of resistance. Soule and Goldman quantified this in 1972 at the US Army Research Institute, measuring oxygen consumption across surface types. Their terrain coefficients have been validated repeatedly and form part of the LCDA equation that Hiko uses to calculate calories.
Terrain Coefficients Used by Hiko
| Terrain | Coefficient | Calorie Impact vs Paved |
|---|---|---|
| Paved road | 1.0 | Baseline |
| Grass | 1.1 | +10% |
| Compact dirt | 1.2 | +20% |
| Gravel | 1.3 | +30% |
| Forest trail | 1.3 | +30% |
| Loose dirt | 1.5 | +50% |
| Snow (packed) | 1.5 | +50% |
| Mud | 1.8 | +80% |
| Sand | 1.5-2.0 | +50-100% |
A coefficient of 1.3 means walking on gravel costs 30% more energy than walking on a paved road at the same speed and grade. Hiko applies these coefficients every second during your workout.
How Hiko Detects Terrain
Hiko uses OpenStreetMap surface data to automatically detect what terrain you are walking on. When Hiko identifies that you have moved from pavement to a gravel trail, Hiko adjusts the LCDA calculation in real time. You can also manually override terrain in the Hiko workout screen if the automatic detection does not match conditions.
Why Generic Apps Get This Wrong
Apple Watch and most fitness trackers use MET-based calorie estimation. MET tables assign a single multiplier to “hiking” regardless of whether you are on pavement or knee-deep snow. The difference can be 50-100% of your actual calorie burn — that is not a rounding error. Hiko accounts for terrain because the LCDA equation was designed for exactly this kind of real-world variability.
Frequently Asked Questions
Does terrain really make that big a difference?
Yes. Research by Soule and Goldman (1972) and Richmond et al. (2019) shows that loose sand can double your energy expenditure compared to a paved road at the same walking speed. Hiko applies these validated terrain coefficients automatically.
How does Hiko know what terrain I’m on?
Hiko queries OpenStreetMap data for surface type at your GPS location. Hiko supports 9 terrain types: paved, compact dirt, gravel, grass, loose dirt, forest trail, snow, mud, and sand. You can also set terrain manually.
What if the terrain detection is wrong?
Tap the terrain indicator during your workout to manually override. Hiko will use your selection until you change it or until Hiko detects a new surface.