A method of inducing forced expiration in a subject is disclosed. The method can include percutaneously placing an injectable microstimulator adjacent at least one thoracic spinal nerve that innervates an intercostal muscle. For example, the microstimulator is placed within 8 cm externally of a neuroforamen through which the spinal nerve emerges from a thoracic vertebra. The method can also entail applying a stimulating electrical current from the microstimulator to the thoracic spinal nerve at a sufficient intensity and duration to induce a forced contraction of the intercostal muscle innervated by that spinal nerve.