A Prediction Model of Arm Push Strength in the Transverse Plane

A study was conducted to determine if a mathematically compact model could be derived to predict arm strength for seated subjects. The purpose of the study was to determine the appropriate algebraic form of the model, and the precise numerical value of the parameters in the model was of secondary interest. An extensive data base of arm strength measurements was compiled for one subject. A detailed analysis of push strength at 65 positions in the shoulder height, transverse plane was performed and a strength prediction model was derived. The forearm was always rotated to the mid-position in this first set of data. A second, more general, set of data was collected at 972 test positions by evaluating 54 (x, y, z) hand locations, three forearm rotations (promotion, mid-position and supination) and six directions of force (left, right, up, down, push and pull). This second set of data was continually referred to in deriving the push strength model. Based on this comparative analysis, it is hypothesized that the algebraic form of the push strength model is appropriate in evaluating more general types of test conditions.