%0 Journal Article
%T Declines in Physical Activity and Cardiorespiratory Fitness After Implementing new National School Guidelines.
%A Kuwahara K
%A Amagasa S
%A Yamaoka K
%J J Adolesc Health
%V 74
%N 2
%D 2024 Feb 9
%M 37815760
%F 7.83
%R 10.1016/j.jadohealth.2023.08.037
%X <B>OBJECTIVE: </B>We examined whether introduction of national guidelines limiting sports club activities at school was associated with adolescents' exercise and cardiorespiratory fitness.<BR><B>METHODS: </B>We conducted interrupted time-series analysis to quantify the changes in prefecture-level aggregated data on exercise or sports activities and 20-m shuttle run (indicator of cardiorespiratory fitness) among adolescents in Japan before (2013-2017) and after (2018-2022) the introduction of the guidelines using data from the National Survey of Physical Fitness, Athletic Performance and Exercise Habits.<BR><B>RESULTS: </B>The introduction of the guidelines was associated with reductions in exercise and sports activities duration (boys, -4.8 [95% CI -5.9, -3.8] min/day; girls, -5.5 [95% CI -6.2, -4.8] min/day) and performance of 20-m shuttle run (boys, -1.2 [95% CI -1.4, -1.0] laps; girls, -2.3 [95% CI -2.5, -2.2] laps).<BR><B>CONCLUSIONS: </B>After introducing guidelines limiting sports club activities at school, levels of exercise or sports and cardiorespiratory fitness declined among adolescents.