“…In a study of randomly selected residents of San Diego, California, 40.9% of participants reported one or more episodes of dropping out of exercise, and 21% reported 3 or more exercise drop-out episodes (Sallis, Hovell, Hofstetter, Elder, Faucher, et al, 1990). Other studies suggest that 50% of adults, both male and female, are likely to drop out of exercise within 6 months of initiation or will fail to maintain physical activity at the intended level (Dishman, 1988;Marcus, Bock, & Pinto, 1997).…”