In some embodiments, a method may include clearing a biological airway. The method may include positioning an inner wearable harness on a torso of a subject. The method may include selectively positioning at least some of a plurality of engines on and/or adjacent at least one treatment area. At least one of the plurality of engines may be releasably couplable to the inner wearable harness. The method may include positioning an outer wearable harness on a torso of a subject. The method may include applying an oscillation force to at least one of the treatment areas using at least some of the plurality of engines. The method may include adjusting the applied oscillation force to the treatment area by activating the outer wearable harness. The method may include mobilizing at least some secretions in an airway within the subject substantially adjacent the at least one treatment area.