However, it is less clear if voluntary exercise can have the same beneficial effects for those living with tetraplegia, in part because their peak power output is only one-third to one-half that achieved during arm exercise in those with paraplegia. In addition, it may be very difficult for those with tetraplegia to be able to exercise for a sufficient duration to achieve a sufficient training effect to either maintain a healthy body composition or reduce the risk of developing the sedentary diseases common to this population. This study will provide the exercise-related energy expenditure data to address this question.