2003 Volume 6 Issue 2 Pages 69-76
This study measured the energy requirements for load carriage on uphill, level and downhill grades. These field data were used to test our algorithms for estimating the energy cost of load carriage. Volunteers carried pack loads of 0 kg, 13.6 kg or 27.2 kg as they walked on level and downhill grades of 0%, 4%, 8.6% and 12% at 1.34 m·s−1. Subjects attempted carries on the uphill 8.6% grade with all 3 loads and on the uphill 4% grade with empty packs. Oxygen uptake (VO2) was collected using portable oxygen monitors. Mean values for VO2 increased as uphill grades and load increased, and decreased with negative grades. The mean subject weight (80.2 kg) was used to calculate load carriage energy costs which were multiplied by a terrain factor of 1.1. The data were split into 5 subsets for statistical analysis: all negative work and level data by load, all level and uphill data with zero load, and all loads on the 8.6% uphill grade. Predicted energy costs using algorithms for level, downhill and no-load uphill carriage agreed with the field data.