Aim: To quantify the global changes in anaerobic fitness (operationalized as power and speed test performance) of children and adolescents.
Methods: Following an extensive review of the literature, 32 studies examining secular changes in power and speed test performance of children and adolescents were analysed. Performance changes were calculated at the country x age x sex x test level using weighted least-squares regression, and were expressed as a percentage of the weighted mean value for all data points in the regression. Negative values indicated performance declines, and positive values indicated improvements.
Results: Changes in power (n=20 802 925) and speed (n=28 320 308) test performance were calculated for 6-19 year olds from 27 countries and five geographical regions, for the period 1958-2003. Overall, power and speed test performances improved at +0.03% and +0.04% per annum, respectively. Performance changes were remarkably similar for boys and girls, and children and adolescents, and somewhat similar for different geographical regions, and high and low income economies. The pattern of change was reasonably consistent over time.
Conclusion: The relative stability in anaerobic fitness test performances in recent decades could be due to the negating effects of increases in fat mass and fat-free mass on anaerobic performance.