In this 22 year longitudinal study researchers from Canada seek to identify long term patterns of involvement in leisure time physical activity, and explore socioeconomic and demographic predictors of physical activity. The results are based on data from 2102 individuals aged 18-60 years in 1981 who also completed a follow-up questionnaire in 2002/04. The researchers conclude that there is a need for continued efforts to increase overall population levels of long term physical activity, particularly among socially disadvantaged groups with respect to income and education.