Genetics of physical activity and physical fitness

Abstract

Abstract Regular physical activity and physical fitness are key contributors to children’s health. It is, therefore, important to understand sources of variation in the phenotypes seen among children and adolescents. Twin and family studies enable calculation of the relative importance of genetic and environmental factors to the observed individual differences. Heritability estimates of physical activity vary widely (0–85%), depending mostly on age. Shared environmental influences decrease from childhood to adolescence with genetic effects becoming more prominent in adolescence. Heritability estimates of most physical fitness traits are stable and high in childhood and adolescence, with only a few studies reporting on shared environmental influences. Gene-finding studies of physical activity and physical fitness for children are sparse, but weight-related genes (LEPR and MC4R) have been found to be associated with physical activity and the ACE and ACTN3 genes with physical fitness. It is concluded that the extent to which heredity contributes to individual differences during childhood and adolescence should be a priority for future research because knowledge of the source of individual differences in physical activity and physical fitness can optimise the choice and timing of physical activity and physical fitness interventions.