Current segment inertial parameter estimation methods can be categorised as either regression, geometric or mass scanning based. Regression methods estimate segment parameters by developing regression equations using cadaver or live subject data. Geometric based methods model body segments as basic geometric shapes and calculate segment parameters assuming uniform density throughout the volume. Mass scanning methods also assume uniform density, but calculate segment shape and volume from mass scanning measurements. The first category does not yield subject specific segment parameters. The other two categories require time-consuming segment measurements and uniform density assumptions. This paper presents a new method for estimating subject specific body segment parameters that utilises work and energy equations and only requires kinematic and kinetic data from a standard walking trial. A preliminary evaluation of this method has been performed and results were comparable to current anthropometric data and average values obtained from mass scanning technology.