The study examined the sensitivity to change of field assessments of handgrip strength and vertical jump following programmatic interventions in physical education settings. Using a naturalistic experimental design, classes of 6th grade students (N = 158) were randomized to receive either an 8-week musculoskeletal strength or plyometric power…

Guided by the life course perspective, this study investigated the developmental antecedents of contact, closeness/warmth, and negativity in young adults' relationships with their parents. Taking the developmental systems approach, we considered interindividual differences in not only initial levels of parenting quality in early adolescence (Grade…

Few longitudinal studies examine how "changes" in parent-child relationships are associated with changes in youth internalizing problems. In this longitudinal study, we investigated how developmental trends (linear change) and year-to-year lability (within-person fluctuations) in parental warmth and hostility across Grades 6 to 8 predict…

This study examines developmental change across adolescence in the similarity of friends versus nonfriends. This differential in similarity is a key aspect of the organization of the peer context of development: The stronger the correlation between friends for an attribute, the more the attribute delineates clustering and divisions of friendships.…