SALLIS, J. F., J. J. PROCHASKA, and W. C. TAYLOR. A review of correlates of physical activity of children and adolescents. Med. Sci. Sports Exerc., Vol. 32, No. 5, pp. 963–975, 2000.
Background: Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results.
Methods: A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3–12) and adolescents (ages 13–18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents.
Results: About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children’s physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents’ physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise.
Conclusion: These consistently related variables should be confirmed in prospective studies, and interventions to improve the modifiable variables should be developed and evaluated.
Important favorable health effects of physical activity for adults are extensively documented and well accepted by health professionals (8,11,13,22). The benefits of physical activity in youth are less well documented (14). However, reviewers have identified at least modest positive effects in the population or subsamples of youth on such health outcomes as aerobic fitness, blood lipids, blood pressure, body composition, glucose metabolism, skeletal health, and psychological health (14,16).
Three groups have issued guidelines specifically for youth physical activity, and there is continuing debate over the amount and types of activity needed for health benefits. Recommendations tend to emphasize daily physical activity and encourage young people to accumulate 30 to 60 min·d−1 (3,5,16) ranging up to several hours per day (5). Because sustained moderate to vigorous physical activity has been associated with specific health benefits, this pattern of activity has also been recommended (5,16). Other recommendations have included activities to promote strength, flexibility, bone health (3), and avoidance of extended periods of inactivity (5).
Population surveys show that many young people are not meeting the guidelines. Although about 80% of adolescents are estimated to spend at least 30 min·d−1 being active, probably less than half are active at least 60 min·d−1 (12). About two-thirds of adolescent boys and one-quarter of adolescent girls report doing 20 min of sustained moderate to vigorous physical activity three times per week (12). Studies using self-report measures usually find more physical activity than those using objective measures (12). Because physical activity has important health benefits in youth and many young people are not meeting established guidelines, improving the physical activity levels of youth is an important public health challenge.
To develop effective physical activity interventions in youth, influences on, and determinants of, activity levels need to be well understood. Data from cross-sectional studies of association can help identify potential mediators of physical activity that can be targeted for change in interventions. Baranowski et al. (1) argue interventions that target strong and consistent modifiable correlates of behavior should be more effective in changing behavior. There have been several reviews of the correlates of youth physical activity (6,15,19–21,23). However, these reviews were not comprehensive, relied on narrative evaluations of the literature (except (21)), and restricted either the age of young people or the categories of variables included in the reviews.
The present review evaluates comprehensively the published studies of correlates of youth physical activity, includes the entire range of potential correlates, encompasses young people aged 3–18 yr, makes a semiquantitative evaluation of the results, and compares results for young people of primary school and secondary school ages. In addition to summarizing methods and results of studies, gaps in the literature are identified and directions for future research are proposed.