Fatness and physical fitness of girls 7 to 17 years

A two-fold approach was used to investigate the association between fatness and fitness of girls 7 to 17 years of age: first, age-specific correlations between fatness and measures of health-related and motor fitness, and second, comparisons of fitness levels of girls classified as fat and lean. A representative sample of 6700 between 7 to 17 years was surveyed. Adiposity (fatness) was estimated as the sum of five skinfolds (biceps, triceps, subscapular, suprailiac, medial calf). Physical fitness included health-related items (step test, PWC 170, the sit and reach, sit-ups and leg lifts, flexed arm hang) and motor performance items (standing long jump, vertical jump, arm pull strength, flamingo stand, shuttle run, plate tapping). Age-specific partial correlations between fatness and each fitness item, controlling for stature and weight, were calculated. In addition, in each age group the fattest 5% (presumably the obese) and the leanest 5% were compared on each fitness test. After controlling for stature and weight, subcutaneous fatness accounts for variable percentages of the variance in each fitness item. Estimates for health-related fitness items are: cardiorespiratory endurance--step test (3% to 5%) and PWC 170 (0% to 16%), flexibility--sit and reach (3% to 8%), functional strength--flexed arm hang (6% to 17 %) and abdominal strength--sit-ups/leg lifts (1% to 8%). Corresponding estimates for motor fitness items are more variable: speed of limb movement plate tapping (0% to 3%), balance--flamingo stand (0% to 5%), speed and agility--shuttle run (2% to 12 %), static strength--arm pull (4% to 12%), explosive strength--standing long jump/vertical jump (11% to 18%). At the extremes, the fattest girls have generally poorer levels of health-related and motor fitness.