Effects of the Girls on the Move randomized trial on adiposity and aerobic performance (secondary outcomes) in low-income adolescent girls

Background: Limited, mixed evidence exists regarding the effectiveness of physical activity interventions on adiposity and aerobic performance in adolescent underrepresented populations.

Objective: To examine effects of Girls on the Move on body mass index z-scores (BMI-z), percent (%) body fat, and aerobic performance in fifth- to eighth-grade underrepresented girls.

Methods: A group randomized trial, involving 12 intervention and 12 control schools in low-income areas, was conducted. Participants (n = 1519) were low-active girls. The 17-week intervention included (a) a physical activity club, (b) two motivational interviewing sessions, and (c) one Internet-based session. BMI-z was determined from measured height and weight; % body fat was assessed using bioelectric impedance. Aerobic performance was assessed using a shuttle run. Demographics, physical activity (accelerometer), and pubertal development were assessed. Linear mixed models, adjusting for baseline, were used to examine group differences in postintervention.

Results: No significant between-group differences in BMI-z existed at postintervention, but % body fat increased less among intervention than control group girls (M_change = 0.43% vs 0.73%). Aerobic performance decreased less in intervention vs control (M_change = -0.39 vs -0.57).

Conclusions: Although the intervention positively impacted % body fat and aerobic performance in underrepresented girls, more research is necessary to determine optimal implementation for yielding greater effects.