Associations between physical activity and physical fitness in preschool children: gender and age differences

This study examined gender and age differences in the association between physical activity (PA) and physical fitness (PF) among preschool children. A total of 425 children participated in the study. PF was assessed using the PREFIT battery, and PA was measured using accelerometers. Multiple linear regression analysis was performed. The results showed that vigorous PA (VPA) was positively associated with lower-limb strength and cardiorespiratory fitness in boys and girls, and was associated with shorter shuttle run times in girls (all p < 0.05). At age three, only light PA (LPA) was positively associated with upper-limb strength (p = 0.033); at age four, moderate PA (MPA) was positively associated with lower-limb strength (p = 0.029); at age five, VPA was associated with muscle strength, cardiorespiratory fitness, and shorter shuttle run times, while MPA was negatively associated with cardiorespiratory fitness (all p < 0.05); at age six, MPA was associated with shorter shuttle run times, while LPA was associated with longer shuttle run times (all p < 0.05). The association between PA and PF among preschool children varies by gender and age. These findings may help inform the design of age- and sex-specific PA programs.