Impact of Pubertal Progression on Physical Activity and Sedentary Time in Adolescent Girls.

PURPOSE Understand how pubertal progression is associated with physical activity behaviors in adolescent girls.

METHODS Longitudinal analysis of early adolescent girls (n = 2778, aged 11.9 y) from the Adolescent Brain Cognitive Development study was conducted. Pubertal trajectories were characterized via latent class analysis. Physical activity measures were derived from Fitbit accelerometers at year 2. Multivariate linear regression analyses examined how pubertal progression predicted physical activity patterns.

RESULTS Girls with early puberty showed fewer steps (b = -506, P < .001), and girls with slow pubertal progression had more steps (b = 580, P < .001), compared with those with typical puberty. Girls with early puberty had more sedentary time (b = 17.9, P < .001), and girls who had slow pubertal progression had less sedentary time (b = -18.3, P < .001), compared with girls with typical puberty.

CONCLUSIONS Girls who developed puberty early had fewer steps and more time spent in sedentary behaviors. A gradient was observed for both steps and sedentary time, with slow progressors engaging in the most steps and least sedentary time, followed by typical progressors, with early progressors showing the fewest number of steps and longer time spent in sedentary behaviors. Girls who progress through puberty early might benefit from additional resources to stay engaged in PA opportunities.