Corsets are often used in the management of patients with a spinal cord injury. They may help to rigidify the patients' trunk which might help some patients to sit upright; their use may also reduce the sensation of dyspnea some patients have while sitting upright. Due to spinal cord injury, abdominal muscles are weakened which can contribute to alter the respiratory function of the patients. But the corset by rigidifying the abdominal wall can improve the efficiency of the respiratory muscles in some patients and reduce dyspnea in the sitting position for some patients. However, when patients with spinal cord injury are followed over time, one can observe that some patients discontinue corset use. The investigators observed that the patients who pursue the corset use still have a significant improvement of their respiratory function with the corset while the patients who have discontinued the use have improved their respiratory function in the upright position (without the corset). As of now, the investigators do not know whether the use of the corset is discontinued because of a spontaneous improvement of the respiratory function or whether discontinuing the use of the corset may help to develop abdominal spasticity and therefore to improve respiratory function. The investigators seek to investigate this issue in order to optimize the management of patients who present spinal cord injury.