Background: Despite the general belief that physical activity in childhood and youth is an important prerequisite for the physical activity in adulthood, there is not much information based on reliable longitudinal studies about the continuity of physical activity from childhood and adolescence to adulthood.
Methods: As a part of a national-level research program called "Cardiovascular Risk in Young Finnus," we studied to what extent leisure-time physical activity at the age of 9, 12, 15, and 18 predicts physical activity nine and 12 years later. A total of 610 9-year-old, 624 12-year-old, 572 15-year-old, and 503 18-year-old boys and girls were studied in 1980. A follow-up measurement was carried out with the same subjects in 1983, 1986, 1989, and 1992. Accordingly, in 1992 they were 21, 24, 27, and 30 years of age. These data concern only the measurements taken in 1980, 1989, and 1992. Physical activity was measured by means of a short questionnaire. A sum index of physical activity (PAI) was computed with the help of five variables.
Results: The correlations between the indices derived in 1980 and 1989, and between those derived in 1980 and 1992, were, with the exception of one group, significant but low varying within a nine-year interval from .18 to .47, and within a 12-year interval from .00 to .27. Corresponding multiple correlations varied from .18 to .53 and from .18 to .30. Participation in competitive sport and the physical education grade were the best predictors of later physical activity.
Conclusions: The results gave support to the conclusion that persistent participation in sport in particular increases the probability of a higher level of physical activity in later life.