Yup, you spell it out the first time and then put (CR) in parentheses, afterwards you can use the abbreviation at will (with a few exceptions - I think abstracts need to stand alone, the same may apply to figures, etc. - but in the text you are good to go.
Minor writing tip, but make sure anything you abbreviate isn't already an established abbreviation for something else in an overlapping literature! Exercise researchers who use PA for "physical activity" drive me absolutely nuts, especially if they are measuring mood as well. In 99% of psychology journals, PA = Positive Affect! Probably irrelevant/old news, but had to bring that up somewhere since I've come across similar problems a few times recently.