“…It is generally held that the level of the excretion of creatinine is a measure of the mass of muscle tissue in the body (Shaffer, 1908;Hodgson and Lewis, 1928;McClugage et al, 1931;Hoagland et al, 1945;Friedemann etal., 1948), although several worker's (Beard, 1932;Keys et al, 1950) have questioned this relationship. Miller and Blyth (1952) have used the excretion of creatinine in the prediction of lean body mass.…”