Generic wearables don't model your external load, terrain, and grade — so their calorie estimates are unreliable under a pack. This gives an estimated loaded-walking energy demand from the military Pandolf equation with the Santee downhill correction, shown with a confidence level.
The RuckLoad Engine gives an estimate, not a lab measurement. Pandolf (1977) is validated for loads up to ~70 kg, grades to 25%, and speeds to 9 km/h; it can under-predict heavier modern loads and, without the Santee correction, over-predict steep downhills. Use it to compare sessions and guide effort, not for medical or clinical decisions. The vest pathway uses the 2024 LCDA vest-load term; when individual resting metabolic rate is unavailable, the app uses a disclosed model default. © 2026 Ken Hoyer / Body Plus Fitness.