Neuromuscular properties of different spastic human joints vary systematically

We quantified the mechanical abnormalities of the spastic wrist in chronic stroke survivors, and determined whether these findings were representative of those recorded at the elbow and ankle joints. System identification techniques were used to characterize the mechanical abnormalities of these joints and to identify the contribution of intrinsic and reflex stiffness to these abnormalities. Modulation of intrinsic and reflex stiffness with the joint angle was studied by applying PRBS perturbations to the joints at different joint angles over the range of motion. Age-matched healthy subjects were used as control.