A longitudinal study of girls from the sixth through tenth grades sought to determine if the extent and type of participation in physical activities changed with age. A sample of 207 girls was selected with 140 completing the survey over 5 years. Participation was measured by activities in interschool teams, intramural activities, community-organized activities, average amount of time per day spent in activities, total number of activities, and frequency of participation in four favorite activities. Included in the study were three major factors related to participation: personal attributes; influence of peers and parents; and opportunity. Findings included: (1) Physical activity declined as the girls matured; (2) Participation in interschool teams and intramural activities dropped off abruptly in grade 10; (3) Satisfaction with and attitude toward physical education was lowest in junior high school; (4) Physical activity for release of tension increased with advancing age while competition declined; (5) Positive influence toward sports by significant others declined along with the image of the female athlete; and (6) Socialization and socioeconomic status separated participants and non-participants in community organized activities. Ten tables, demonstrating the findings, are included in the text. (JD)