Comparison and Relationship of Body Composition Methods in Swimmers Aged 12 to 18

Abstract

Three body composition methods for determining body fat (%) and fat-free mass (FFM) were compared in youth competitive swimmers (X age ±SD = 15.06 ±1.77 years.). Relationship among methods was also examined. Thirty-one youth including 17 females (55%) and 14 males (45%) volunteered. Subjects were requested to refrain from exercise on the test day and were randomly assigned regarding order of testing methods applied. Measurements from a lunar dual-energy X-ray absorptiometry (DEXA) instrument, hydrodensitometry (HD) employing underwater weighing and skinfold thickness (SK) employing the Slaughter et al (1988) equation were compared with respect to %fat and FFM. Lung residual volume was estimated from vital capacity after Wilmore (1969). A 1-way ANOVA revealed no significant differences (p < 0.05) between methods. The mean %fat measured by DEXA was 17.76±7.85, by HD, 18.51±6.18, and with SK, 18.69±5.01. Mean FFM measured by DEXA was 49.49±10.27, by HD, 49.52±9.97, and by SK 49.48±9.76. Bivariate correlations (Pearson r's) for %fat were 0.88 between DEXA and HD, 0.95 between DEXA and SK, and 0.80 between HD and SK. Fat-free mass correlations were 0.98 between DEXA and HD, 0.98 between DEXA and SK, and 0.97 between HD and SK. These results indicated excellent agreement among methods for indirectly determining %fat in youth competitive swimmers.