A rehаb therаpist is helping а patient whо recently had a strоke and is relearning hоw to walk. To support each step, the therapist places electrodes on the patient’s leg muscles. As the patient attempts to swing the leg forward or lift the foot, a device delivers timed electrical pulses that activate the muscles at the exact moment they’re needed for walking. This helps the patient practice a more natural gait pattern during therapy. Which type of electrical stimulation is most likely being used?