Physical fitness before and during the COVID-19 pandemic: Results of annual national physical fitness surveillance among 16,647,699 Japanese children and adolescents between 2013 and 2021

Secular trends in physical fitness of rural Chinese children and adolescents aged 7–18 years from 1985 to 2019

“…The trends were similar to nationwide research and Chinese urban areas 11 , but there were different trends in some regions of China (first stable then worsened or improved) 13,35 . The flexibility of boys worsened and improved in girls in Hong Kong from 1998 to 2015 53 which was similar to our findings A 30-year negative trend was observed in Africa 37 , but a positive trend was observed in Japan in the previous decade 36 . For some developed countries, such as Croatia 14 , Portugal 38 , Lithuania 39 , rural Germany 42 , Dutch 43 , Poland (Krakow) 47 , and Brazil 48 , a large number of studies have shown that flexibility has worsened.…”

“…The speed for both sexes improved after 2010, which was similar to other Chinese studies 2,11,12,35 and a Japanese study (2013-2019) 36 , which both demonstrated positive trends in recent years. Some studies found that Chinese urban children and adolescents also show positive trends in speed after 2010 as well, but positive trends were more pronounced in rural areas 11,12 .…”

“…The trend was similar to other Chinese studies 2,11,12,35 in Chinese urban areas 11,12 . However, we found that the explosive power of rural boys improved from 2015 to 2018 in Shanghai, China 13 , and improved in Japan in the last decade 36 . Some developed countries, such as Slovenia (until 2014) 21 , Lithuania 39 , Italy 41 , Poland 47 , and Brazil 48 , reported negative trends at the beginning of the twenty-first century or throughout the observed period, with many of these studies showing no significant changes 15,39,41,47 or improvement for girls in recent years 21 .…”

“…The negative trends were similar to nationwide researchs and Chinese urban areas 2,11,35,53 , but improvements were also observed for children aged 7-12 years from 2005 to 2014 11,12 . Cardiorespiratory fitness improved in Japan but worsened after 2019 36 . Previous studies have shown negative trends in cardiorespiratory fitness in children and adolescents in many countries around the world 2,11,13,14,37,39,48,54,55 and some studies have found that cardiorespiratory fitness has been stable (boys or girls or both sexes) in recent years 35,41,42,49,56 .…”

“…However, Xinjiang, China, found positive trends in recent years only in boys aged 13-18 and worsened in both boys and girls in Hong Kong (sit-ups for both sexes) 35,53 , which differs from this study and suggests differences between different regions of China. The performance of sit-ups improved in Japan but declined after 2019 36 . In some developed countries, increasing or stable sit-up performance was observed in Croatia 14 , Slovenia 15 , Greece 50 Portugal 38 and Germany 42,49,56 , and negative trends were found only in Brazil 48,55 and the United Kingdom 57 .…”