Changes in Physical Fitness Among Preschool Children From Krakow (Poland) From 2008 to 2018

Background: The aim of this study was to analyze the secular changes of the physical fitness of preschool children from Krakow, Poland between 2008 and 2018. Methods: The study group consisted of 2143 children (3- to 7-y-olds; 2008 cohort included 1037 children and the 2018 cohort included 1106 children). The following physical fitness tests were carried out: overhead medicine ball throw, standing broad jump, sit-and-reach test, and handgrip strength. Statistical differences between the cohorts were obtained using 2-way analysis of variance and Tukey tests. Results: Negative changes were noted for the standing broad jump and its relative results among boys. A negative trend was also observed for flexibility and ball throw. Positive changes were noted for the standing broad jump among girls, as well as the absolute and normalized results of handgrip strength in both sexes. Besides the flexibility, observed discrepancies were practically significant between the age groups. Differences between the cohorts reached practical significance in the case of absolute and normalized handgrip strength. Conclusions: There was at least partial progress in the children's fitness. Physical fitness, in turn, is one of the most important health markers. Moreover, its low level is a predictor of diseases, including metabolic and cardiovascular ones, lower academic performance, and psychosocial problems.