RESUMO
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.