Breathlessness is an extremely common and uncomfortable symptom that is reported in more than two-thirds of persons with tetraplegia. This disordered pulmonary function is due to respiratory muscle paralysis or to sympathetic denervation results in a restrictive impairment and airway hyperreactivity, respectively. These restrictive and obstructive dysfunctions have been associated with the symptom of breathlessness. However, mechanisms contributing to dyspnea in persons who have tetraplegia are not well understood. It has been demonstrated that persons with tetraplegia have an increased prevalence of breathlessness and may have an altered breathing pattern. The purpose of this study is to determine the breathing pattern at rest and measure the changes in breathing after a bronchodilator treatment (a medicine commonly used to treat asthma that relaxes and opens up airways). The determination of breathing pattern is done by measuring the movements in the chest wall while breathing. This design will elucidate differences in breathing patterns between those with tetraplegia and controls, as well as demonstrate the effect of bronchodilatation on motor drive and timing. Knowledge of the intraindividual variability and mean values of the components of the breathing pattern will improve our understanding of breathlessness in these individuals.