A method is described for providing deficit-adjusted adaptive assistance during movement phases of an impaired ankle. The method includes determining, on the processor, a value for a deficit parameter for each movement phase of a compound ankle function based on a difference between a parameter trace for a normal subject and the parameter trace for an impaired subject. The method further includes determining, on the processor, an adaptive magnitude for the robot-applied torque based on the value for the deficit parameter. The method further includes applying, to the robot joint, the adaptive magnitude for the robot-applied torque in only a first plane for the current movement phase, based on an adaptive timing. An apparatus is also described for providing deficit-adjusted adaptive assistance during movement phases of the impaired ankle.