The aim of this study was to determine whether changes in fitness performance could be explained by changes in body fatness. Two hundred seventy-nine 10- to 12-year-old children were tested in 1985 as part of a national survey. They were matched for age, sex, body-mass index, and triceps skin-fold thickness with 279 children from a 1997 survey. Average speeds on the 1.6 km walk/run test were compared. Children from the 1997 survey performed significantly worse than their matched peers from the 1985 survey. The decline in performance was evident for boys, girls, and all children. Matching for fatness reduced performance differences by about 61% in boys, and 37% in girls. Declines in fitness performance in this population have not been entirely due to increases in fatness.
The authors are with the School of Health Sciences, University of South Australia, Holbrooks Rd., Underdale SA 5032, Australia.