Relationship between Physical Activity and Body Composition in Young Children

Abstract

[Purpose] One of the causes of obesity in young children is a decrease in physical activity (PA). In young children, PA is also associated with risk factors for cardiovascular diseases as well as health-related indicators such as obesity and physical fitness. The purpose of this study was to clarify the relationship between PA and body composition in young children. [Participants and Methods] PA, Fat Mass Index (FMI), and Free Fat Mass Index (FFMI) of children aged 5 to 6 years were measured. An InBody520 (Biospace, Co., Ltd.) was used to measure FMI and FFMI, while PA was measured for 7 days with an Active Style Pro (Omron Healthcare Inc.) worn at the waist. The intensity of PA was divided into two levels: 1.5 to 3.0 Metabolic Equivalents (METs) as Low PA, and over 3.0 METs as Moderate-to-Vigorous PA (MVPA). [Results] Significant negative correlations were found between MVPA and FFMI, step count and FFMI, MVPA and the Kaup index, and step count and the Kaup index. MVPA showed significantly lower values on holidays than on weekdays. [Conclusion] The results of this study indicate that the Kaup index and FFMI are low in young children with high PA, suggesting that PA, FFMI, and the Kaup index are interrelated. The results also show that MVPA significantly decreased on holidays compared to weekdays.