Critical hours: physical activity and sedentary behavior of adolescents after school

Pediatr Exerc Sci. 2008 Nov;20(4):446-56. doi: 10.1123/pes.20.4.446.


The present study examined physical activity and sedentary behavior patterns of adolescents between 15.30h and 18.30h. The sample for this study is 1,484 (boys: n = 561; girls: n = 923). Boys and girls reported 21 and 19 min of physical activity and 24 and 26 min of homework respectively during this period. Technology-based sedentary behavior (TV viewing, computer and video game use) was significantly higher in boys than girls (boys = 50 mins; girls = 35 mins; p < .05). The most prevalent behaviors after school are technology-based sedentary behavior, homework and physical activity. During these hours, engagement in physical activity does not appear to displace time spent doing homework.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Computers
  • Exercise*
  • Female
  • Humans
  • Leisure Activities*
  • Life Style*
  • Male
  • Sex Distribution
  • Sex Factors
  • Television
  • United Kingdom
  • Video Games