Participants in this study will be randomly assigned to receive either OMT or sham treatments once a week for 13 weeks. Outcome measures will be obtained at baseline; immediately following the first treatment; at 4, 8, and 12 weeks after initiation of treatment; and 4 weeks after termination of the treatment. Outcome variables include pulmonary function tests; quality-of-life questionnaires (including emotional functioning, fatigue, and dyspnea); and measurements of exercise tolerance and chest wall mobility.