Prediction of trunk muscle areas and moment arms by use of anthropometric measures

The prediction of five internal muscle variables extracted from computed tomography scans was attempted using 27 anthropometric variables. Stable regression equations are presented for the prediction of the cross-sectional area of the rectus abdominis, psoas, and erector spinae, as well as for the moment arm of the erector spinae. No stable regression equation was found for the prediction of the moment arm of the rectus abdominis, and the results indicated that the method was group dependent. These findings have implications for human modeling studies that use estimated parameters for the internal muscle variables.