Full-time wheelchair users with tetraplegia between the ages of 18 and 65 will be recruited for the study. They will be free of pressure sores, free from any shoulder pain that would prevent them from propelling a manual wheelchair, and have no history of cardiopulmonary disease. A maximum of 50 subjects (fifteen for Phase I and II, and 15 or Phase III, and five for subject drop-out) will be recruited. In Phase I, participants will be asked to propel a PAPAW and their own wheelchair, attached to a wheelchair roller system through three resistance conditions. In Phase II, participants will be asked to propel both wheelchairs over activities of daily living. Finally, Phase III consists of a four-week trial including a two-week test with subjects' own wheelchairs (i.e. own chair trial) and a two-week test where they were provided with the PAPAW (i.e. PAPAW trial). The order of the own chair trial and the PAPAW trial will be randomized.