Experimental Design: Patients will perform an test, first on land, and in a week time in a underwater treadmill. The data will be collected in four distinct moments: 1- anaerobic threshold (AT), 2- respiratory compensation point (RCP), 3- maximal effort (ME) and recovery (R). We will compare the following variables: test total time; perceived exertion scale (Borg); Heart rate (HR); Oxygen consumption (VO2); Carbon Dioxide production (VCO2); Oxygen pulse (VO2/FC); the ventilatory efficiency (VE/VO2) and (VE/VCO2); Respiratory quotient (VCO2/VO2); Systolic and Diastolic blood pressure; electrocardiographic changes, compatible with ischemia or arrhythmia.