Single-Input-Single-Output frequency response functions and coherences of first and second perturbation round. The left panel depicts the FRF from the sway angle to the ankle joint torque; the right panel the FRF from the sway angle to the hip joint torque. The lower panels show the coherence between the perturbation, and the ankle joint torque, hip joint torque, and the sway angle. Similar gains and phases of the frequency response functions of the first and second perturbation round indicate that participants did not change their balance control strategy.
Boonstra et al. Journal of NeuroEngineering and Rehabilitation 2013 10:23 doi:10.1186/1743-0003-10-23