During physically heavy work tasks the musculoskeletal tissues are exposed to both mechanical and metabolic loading. The aim of the present study was to test a biomechanical model for prediction of whole-body energy turnover from kinematic and anthropometric data during load carrying. Total loads of 0, 10 and 20 kg were carried symmetrically or asymmetrically in the hands, while walking on a treadmill (4.5 km h⁻¹) horizontally, uphill, or downhill the slopes being 8%. Mean values for the directly measured oxygen uptake ranged for all trials from 0.5 to 2.1 1 O₂ min⁻¹, and analysis of variance showed significant differences regarding slope, load carried, and symmetry. The calculated values of oxygen uptake based on the biomechanical model correlated significantly with the directly measured values, fitting to the line Y=0.990X+0.144, where Y is the estimated and X is the measured oxygen uptake in 1 min⁻¹. The close relationship between energy turnover rate measured directly and estimated based on a biomechanical model justifies the assessment of the metabolic load from kinematic data.