A method for normalization of oxygen cost and consumption in normal children while walking

Measurement of oxygen use is helpful in determining energy consumption in c hildren with walking abnormalities; however, no statistically valid measure ments of nondisabled children have been established using a telemetric syst em. Data from 94 nondisabled children, ages 5-15 years, were collected usin g the Cosmed K2 oxygen analysis system. Oxygen cost, measured in milliliter s O-2/kg/m walked, and oxygen consumption, measured in milliliters O-2/kg/m in, were correlated to inverse body surface area (IBSA) measured in meters( -2). Linear relationships between oxygen cost and IBSA and between oxygen c onsumption and IBSA were best described by the following equations: oxygen cost = 0.256 (IBSA) + 0.052 (r = 0.806) and oxygen consumption = 17.635 (IB SA) + 4.956 (r = 0.758). From these data, equations were derived to calcula te predicted oxygen cost and predicted oxygen consumption for each child. I ndices were developed to express the difference between a measurement and t he predicted mean in reference to the normal variation. These equations and indices can help quantify the variation of energy use of children with wal king abnormalities when compared with their nondisabled peers. Additionally , the indices enable multiple tests from one subject to be compared, regard less of a change in age, height, and weight between measurements.