An apparatus includes a frame, a sensor, and an electric stimulator. The frame is removably couplable to a portion of a limb. The sensor is configured to produce a first signal associated with a gait characteristic at a first time, and a second signal associated with the gait characteristic at a second time, after the first time. The electric stimulator is removably coupled to the frame and is in electrical communication with an electrode assembly and the sensor to receive the first signal substantially at the first time and the second signal substantially at the second time. Based in part on the gait characteristic at the first time, the electric stimulator sends a third signal to the electrode assembly to provide an electric stimulation to a portion of a neuromuscular system of the limb substantially during a time period defined between the first time and the second time.