Background The aim of this study was to investigate physical fitness and physical activity (PA) of 6-7-year-old children just before entering school according to their sports club (SC) participation and weight status, and to examine possible associations of their body mass index, fat mass and fat-free mass with physical fitness and PA. Methods A total of 256 preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and objective PA by 7 day accelerometry. Body composition was estimated using two skinfold thickness parameters. SC participation and parental data were assessed by questionnaires. Results Children participating in SC had higher moderate-to-vigorous PA, vigorous PA and cardiorespiratory fitness than children not participating in SC. Overweight children had lower results in cardiorespiratory fitness and all weight-bearing fitness tests, and better results in handgrip strength test in comparison with normal weight children. Significant associations were found between body composition indices and physical fitness tests. PA level was associated with fat-free mass and physical fitness but not with fatness indices. Conclusions Weight-status and body composition together with PA level were associated with physical fitness level. The differences in physical fitness based more upon weight status than SC participation among 6-7-years old children.

Aim We explored the cognitive abilities, health behaviour and cardiorespiratory fitness of preschool Estonian children aged 6–7 and any association with parental education, attending sports clubs and gender. Methods Data were obtained from 256 children recruited from 13 randomly chosen kindergartens in Tartu, Estonia. Cognitive abilities were assessed using the modified Boehm Test of Basic Concepts – Third Edition. Objective physical activity (PA) intensity and sedentary levels were measured over seven days by accelerometry. To assess cardiorespiratory fitness, we used the 20‐m shuttle run from the PREFIT test battery. Parents reported their educational attainment, together with their child's sports club attendance, sleep duration and screen time. Results Children from more highly educated families had significantly better test results for conceptual skills, verbal abilities and cardiorespiratory fitness. PA levels, cardiorespiratory fitness and perception and conceptual skills test results were better in children who attended sports clubs. Higher cardiorespiratory fitness level, shorter screen time and sleep duration were associated with better conceptual skills. Conclusion Conceptual skills and verbal abilities were better in the children of more highly educated families and if they attended sports clubs. Children's cognitive abilities may benefit from better cardiorespiratory fitness, reduced sedentary activity and less screen time.

The objective of this study was to investigate physical fitness of preschoolaged children just before entering school according to their body mass index, and to examine possible associations of body mass index, fat mass and fat-free mass with physical fitness in preschool-aged children. Two hundred and fifty-six preschoolers aged 6 to 7 years participated in the study. Physical fitness was assessed using PREFIT test battery and body composition was estimated using four skinfold thickness parameters. Overweight children had lower cardiorespiratory fitness and lower results in all weight-bearing fitness tests, and better handgrip strength test result in comparison with normal-weight children. Significant associations were found between body composition indices and the results of physical fitness tests. Higher BMI associated negatively with weight-bearing physical fitness tests. The results of the research indicate that weight-status and body composition have significant effect on physical fitness in 6–7 years old preschoolers.