Patterns of physical activity among German adolescents: the Berlin-Bremen Study.

Patterns of leisure-time physical activity among 932 West German boys and girls from two distinct socioeconomic groups were examined longitudinally over a 2-year period beginning with seventh to eighth grade students. Activity indices reflect the weekly time spent in activities, the weekly frequency of participation, and the average duration per activity episode. The indices refer to all activities, to moderate or vigorous activities, or to each individual activity. The average seventh to eighth grade student spent 10.1 hr/week engaged in all of the activities measured. Overall, the time devoted to these activities declined by 10% during the 2-year study period, with the relative decrease being larger for vigorous than for moderate activities. The decline in time spent in vigorous activity was due to a decreased frequency of participation; whereas the decline in moderate activity was primarily attributable to the decreased average duration per episode. Boys spent about 3 hr/week more in all activities than girls, with the difference largely being due to the boys' greater participation in vigorous activities. Weekly activity time among girls did not vary substantially with socioeconomic status. However, compared with boys of higher socioeconomic status, boys in the lower socioeconomic grouping were 2-3 hr/wk more active because they devoted more time to moderate activities. The results indicate that the identified activity patterns in the population strongly depend on the activity dimensions on which the measure focuses.