This study will test whether using the Biodex BioStep Semi Recumbent Elliptical for the chronic obstructive pulmonary disease (COPD) patient with arthritic limitations will improve participation in a pulmonary rehab program compared to the Nustep elliptical. The main outcome of participation will be measured by the number of exercise sessions the patient is able to complete during their pulmonary rehabilitation program. In addition, distance walked in six minutes, dyspnea score, rate of perceived exertion (RPE) score, Pain Scale Index score, and finally, the Dartmouth Quality of Life index (DQL) will be assessed in both groups. It is believed that the new machine will provide better overall outcomes compared to the traditional machine.