A prosthetic joint device includes a foot portion and a main body pivotally coupled to the foot portion at a first joint. A first compliant member is coupled to the main body and foot portion. A first clutch is coupled to the first compliant member. An actuator is coupled to the first clutch to lock and unlock the first clutch and engage and disengage the first compliant member. A control system is coupled to the actuator to control the actuator based on a gait activity. The first clutch is locked to engage the first compliant member. A second compliant member is coupled to the main body and foot portion. A sensor is coupled to the prosthetic joint device to measure a physical state of the prosthetic joint device. The engagement and disengagement of the first compliant member is timed based on the physical state of the prosthetic joint device.
