An improved ankle joint device is provided. In one aspect, the device provides two stages of dorsiflexion resistance biasing a first splint member (or other attachment member that follows the angular displacement of a wearer's lower leg or foot) against dorsiflexion movement within an active angular range of dorsiflexion, corresponding to second and third rocker phases of a wearer's gait； in addition to a phase of plantarflexion resistance biasing the first splint/attachment member against plantarflexion movement within an active angular range of plantarflexion, corresponding to a first rocker phase. In another aspect, an equilibrium or neutral angle between a wearer's foot and tibia at which the device applies no biasing forces is adjustable by adjusting the angle at which a second splint/attachment member is fixed relative to a joint body. Typically, the second splint member is secured to a wearer's lower leg, and the first splint member is secured to a wearer's foot.
