Frequency analysis was employed to identify the relationship between movements of the body and the resultant torque on the groundplane. The results of these measurements were compared with computer simulations of the mathematical relationships between torque and movements. Differences between measurements and simulations were examined. It seems that a low spectral signal-to-noise ratio density and nonlinearities in the relationship affect frequency behaviour. Further differences due to biological controls between parts of the body are apparent. From the analysis it can be concluded that not only the biomechanical behaviour of the body but also human biological co-ordination of parts of the body affect the relationship between torques and movements.