The prediction of metabolic energy expenditure during gait from mechanical energy of the limb: a preliminary study.

Measurements of metabolic energy consumption and free-walking velocity were recorded for four persons with trans-femoral amputation with variations of prosthesis mass and mass distribution. Hot-film anemometers, rate gyroscopes, and a force platform were used to measure prosthetic limb segment velocities and ground reaction forces. Metabolic energy consumption for the nine configurations of mass and mass distribution averaged 1.177 cal/kg/m with a standard deviation of +/- 0.052 cal/kg/m. Two measures of mechanical work of the amputated extremity, one based on power developed across joints (W1) and the other based on changes in energy of the body segments (W2), were computed to be 0.162 +/- 0.014 and 0.175 +/- 0.025 cal/kg/m, respectively. A linear regression model led to rejections of both W1 and W2 as predictors of metabolic energy expenditure of the amputee at a significance level of 0.05.