Physical inactivity is both a national and worldwide challenge as it increases risks for several health problems such as obesity, whereas physical activity decreases risks. Physical activity is often related to motor skills in children and adolescents. However, the strength of the association varies in different age groups and by the type of motor skill. Inconclusive results exist on differences in motor skills between girls and boys at preschool age. It is unclear which factors should be targeted in motor skills improvement and physical activity increase.

The main object of this study was to provide in-depth knowledge of the association between motor skills, physical activity, and sedentary behavior in 5–6- year-old children in the framework of Newell’s constraints model of motor development. The individual and family-related associations with motor skills and physical activity in early childhood were studied. The data from the STEPS Study (Steps to the healthy development of children) with 1797 parents and their children were used.

No significant associations were found between motor skills and physical activity or sedentary time in preschool aged children. Body weight and body fat percentage among girls were associated with some motor skills. Healthy weight children had significantly better scores in nearly all motor skills than their overweight or obese peers. Parents’ physical activity and sedentary behavior were associated with those of their children in early childhood. Attendance in day care and higher education level of parents were positively associated with physical activity and some motor skills. This study showed that the associations between physical activity and motor skills may be invisible in early childhood. Unhealthy body weight may serve as a constraint in motor skill development. A parental role model is of importance in early childhood in developing a physically active lifestyle and may prevent overweight or obesity.