Objectives: The purpose of this study was to examine the relationship between girls' sexual maturation (age of menarche) and physical activity and sedentary behaviors.
Methods: Data were collected from a national representative sample of girls in 2010 (pre-menarcheal girls n = 583, post-menarcheal girls n = 741). Physical activity (times/week and hours/week) and screen-based sedentary time (minutes/day) including television/video/DVD watching, playing videogames, and computer use were self-reported.
Results: Pre-menarcheal girls engaged significantly more times in physical activity in the last 7 days than post-menarcheal girls (3.5 ± 1.9 times/week vs. 3.0 ± 1.7 times/week, P < 0.001). There was no significant difference between pre-menarcheal and post-menarcheal girls in time (hours/week) spent in physical activity. Post-menarcheal girls spent significantly more minutes per day than pre-menarcheal girls watching TV, playing videogames, and using computers on weekdays (TV: 165.2 ± 105.8 vs. 136.0 ± 106.3, P < 0.001; videogames 72.0 ± 84.8 vs. 60.3 ± 78.9, P = 0.015; computer: 123.3 ± 103.9 vs. 82.8 ± 95.8, P < 0.001) and on weekends (TV: 249.0 ± 116.2 vs. 209.3 ± 124.8, P < 0.001; videogames: 123.0 ± 114.0 vs. 104.7 ± 103.5, P = 0.020; computer: 177.0 ± 122.2 vs. 119.7 ± 112.7, P < 0.001). After adjusting analyses for age, BMI, and socioeconomic status, differences were still significant for physical activity and for computer use.
Conclusion: Specific interventions should be designed for girls to increase their physical activity participation and decrease time spent on the computer, for post-menarcheal girls in particular. Am. J. Hum. Biol. 28:471-475, 2016. © 2015 Wiley Periodicals, Inc.
© 2015 Wiley Periodicals, Inc.