近年來許多研究皆顯示兒童及青少年的身體活動與成年期的心血管疾病的危險因子及肥胖有密切關係，有研究顯示兒童的身體活動量隨著時代演進而逐漸下降，因此，兒童的身體活動逐漸受到重視，如何精確評估兒童及青少年的身體活動是一大挑戰。本文中將討論身體活動的定義及評估身體活動的方法，作為日後醫療人員評估身體活動之參考。

In recent years, many research results indicate that adult cardiovascular disease risk factors and obesity are associated with physical activity during childhood and adolescence. Since evidence indicates that there is a decline in physical activity during childhood and adolescence, the physical activity of children and adolescents has been given more attention lately. However, it is a particular challenge to accurately assess physical activity in children and adolescents. The article is a review of the definition and methods for assessment of physical activity. It can be used as clinical references for health professionals to perform an assessment of physical activity among children and adolescents.