An article in the Montreal Gazette by Jill Barker called Turn Excuses Into Action talks about the main excuses that couch potatoes use to get out of exercising.  

An excuse that a lot of people use is “I’m not a gym person.” You don’t have to go to a gym to exercise. Biking, canoeing, swimming, running or even taking a walk in the park count as legitimate forms of exercise.  This way nobody is staring at your body or if you are wearing the latest in spandex fashions. 

One of the main excuses that people use is “I am not in good enough shape to exercise.” This of course is a self-defeating excuse with no way out of the dilemma. Barker suggests that the only way out of this one is to keep your goals attainable and start out slowly. In other words, get off the couch and exercise anyway!