Temporal trends in the sit-ups performance of 9,939,289 children and adolescents between 1964 and 2017

ABSTRACT

We estimated international/national temporal trends in sit-ups performance for children and adolescents, and examined relationships between national trends in sit-ups performance and national trends in health-related/sociodemographic indicators. Data were obtained by systematically searching studies reporting on temporal trends in sit-ups performance for apparently healthy 9–17 year-olds, and by examining nationally representative fitness datasets. Trends at the country-sex-age level were estimated by sample-weighted regression models relating the testing year to mean sit-ups performance. International/national trends were estimated by a post-stratified population-weighting procedure. Pearson’s correlations quantified relationships between national trends in sit-ups performance and national trends in health-related/sociodemographic indicators. A total of 9,939,289 children and adolescents from 31 countries/special administrative regions between 1964 and 2017 collectively showed a large improvement of 38.4% (95% CI: 36.8 to 40.0) or 7.1% per decade (95% CI: 6.8 to 7.4). Large international improvements were experienced by all age and sex groups, with the rate of improvement slowing from 1964 to 2000, stabilizing near zero until 2010, before declining. Trends differed between countries, with national trends in vigorous physical activity a strong, positive correlate of national trends in sit-ups performance. More sit-ups data are needed from low- and middle-income countries to better monitor trends in muscular fitness.

PROSPERO registration number

CRD42013003657.

KEYWORDS:

• Secular changes
• physical fitness
• fitness testing
• muscle endurance
• youth

Acknowledgments

We would like to thank: (a) the authors of the included studies for generously clarifying details of their studies and/or for providing additional data; and (b) Dr Diana Dimitrova, Dr Gregor Jurak, Dr Tetsuhiro Kidokoro, Dr Dae-Yeon Kim, Dr Yang Liu, Dr Duncan Macfarlane, Dr Shingo Noi, Dr Gregor Starc, and Dr Koya Suzuki for their help with national fitness surveillance data from Bulgaria, China, Hong Kong, Japan, the Republic of Korea and Slovenia.

Compliance with Ethical Standards

All authors declare no conflicts of interest and received no external financial support was received for this project.

Contributors

GRT and TK developed the research question and designed the study; had full access to all data and take responsibility for the integrity of the data; and led the statistical analysis, synthesis of results, and the writing of the report. All authors contributed to the interpretation of results, editing and critical reviewing of the final report, and approved the final report.

Disclaimer

The content and views expressed in this article are those of the authors and do not necessarily reflect those of the Government of Canada.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The datasets analysed in this review are available from the corresponding author on reasonable request.

Supplemental material

Supplemental data for this article can be accessed here.