Electrocardiogram: The electrocardiographic tracings were performed by the Ecafix® CardioPerfect 5.0 device coupled to a microcomputer with compatible HD and a 1.4 MB drive 60 Hz filter. Approved by the Food and Drug Administration (FDA), the records were taken at rest, on days when they had not performed exercises, and according to the best clinical practice. The interpretation of the ECG abnormalities was completed by an experienced specialist and according to the criteria established by Corrado et al., for which they were classified into two categories: