Guseman EH, et al. - Since physical activity is known to vary by socioeconomic status, physical fitness may be expected to vary similarly, researchers investigated disparities in physical fitness performance among a nationally-representative sample of 6–11-year-old children residing in the United States. They performed secondary analysis of physical fitness data of children (n = 686) from the nationally representative National Health and Nutrition Survey (NHANES) Youth Fitness Survey (NNYFS) 2012. Income differences were evident among girls in physical fitness performance, but not among boys. Girls from lower income groups (< 130% FIPR and 130–349% FIPR groups) displayed significantly lower cardiorespiratory endurance and core muscle strength compared with those from the highest income group (≥ 350% FIPR). Such results illustrate the need to support health-promoting physical activity among girls from disadvantaged backgrounds before the adolescent period.