Predicting Metabolic Cost of Running with and without Backpack Loads

摘要

A mathematical equation to predict the metabolic cost of standing or walking (Mw) has been developed. It is, however limited to speeds < 2.2 m/s and overestimated the metabolic cost of walking or running at higher speeds. This study's purpose was to develop a mathematical model for the metabolic cost of running (Mr)in order to predict the metabolic cost under a wide range of speeds, external loads and grades. Twelve male subjects were tested on a level treadmill under different combinations of speed and external load. Speed varied between 2.2 to 3.2 m/s using 0.2 m/s intervals and external loads between 0.30 kg with 10 kg intervals. Four of the subjects were also tested at 2 and 4% incline while speed and load remained constant (2.4 m/s, 20 kg). The model developed is based on Mw and is proportionately linear with external load (L) carried as follows: Mr = Mw - 0.5 (1-0.01L) (Mw-15L-850) -- in water. The correlation coefficient between predicted and observed values was 0.99 (P<0.01) with SER of 7.7%. The accuracy of the model was validated by its ability to predict the metabolic cost of running under different conditions extracted from the literature. A highly significant correlation (r = 0.95, P<0.02, SER = 6.5%) was found between our predicted and the reported values. Keywords: Work efficiency, Load carriage, Backpack load, Mathematical prediction, Ergonomics.