BACKGROUND: This study aimed to present step-determined physical activity trends in adolescents with different activity levels over a period of 10 years. METHODS: Pedometers were used to monitor weekly physical activity in 1855 boys and 2648 girls aged 15-19 years recruited from 155 schools in the Czech Republic between 2009 and 2018. Trends for average steps/day and percent of accumulating various levels of steps/day (<10,000, 10,000-13,000, and >13,000 steps/d) were analyzed by sex. RESULTS: There was a statistically significant decrease in average steps/day between 2009-2010 and 2017-2018 in boys from 12,355 (3936) steps/d to 10,054 (3730) steps/d and girls from 11,501 (3278) steps/d to 10,216 (3288) steps/d. The percent accumulating <10,000 steps/d increased by 21% in boys and 12% in girls. The percent achieving >13,000 steps/d decreased by 17% in boys and 10% in girls. CONCLUSIONS: Objectively collected evidence indicates an overall decrease in Czech adolescents' steps/day over a 10-year period concurrent with an increase in the percent of boys and girls accumulating <10,000 steps/d. These trends are concerning as they portend a decline in physical activity as adolescents transition to adulthood and continue to age, which also may have major health implications.

Faculty of Physical Culture Palacký University Olomouc Olomouc Czech Republic

Institute of Sport Science The Jerzy Kukuczka Academy of Physical Education Katowice Poland

Walking Behavior Laboratory University of North Carolina at Charlotte Charlotte NC USA

References provided by Crossref.org

Adolescent physical activity during school days: a comparative study before and after COVID-19 pandemic restrictions