The purpose of this paper is to review the exercise physiology literature on spinal cord injured individuals with quadriplegia performing voluntary arm exercise and/or electrically stimulated leg exercise. The effects of level of injury, active muscle mass, and sympathetic dysfunction on acute physiologic adjustments during exercise testing and chronic training adaptations are discussed. Several topics for future research are suggested, including methods to achieve higher aerobic/cardiovascular fitness, reduce secondary cardiovascular/pulmonary disabilities and related health care costs, and promote health, wellness, and an active lifestyle.