WHOLE BODY COMPOSITION AND BONE MINERAL DENSITY MEASURED BY DUAL-ENERGY X-RAY ABSORPTIOMETRY IN YOUNG SWIMMERS

Abstract

Height-adjusted indexes that reflect muscularity and fatness have recently gained great momentum in exercise and sports sciences as these indexes are considered to more accurately predict general body composition (BC) status, compared to body mass index. The aim of the study was to compare BC components and height-adjusted indexes between young swimmers and non-athlete controls. Thirty-four young volunteers, consisting of eighteen swimmers (male n=8; female n=10) and sixteen college students serving as a control group (male n=8; female n=8), participated in this study. BC and whole-body bone mineral density (BMD) were measured using DXA and height-normalized indexes of fat mass (FM) and lean mass (LM) were calculated. Two-way (group*sex) ANOVA was used to compare the BC components within and between the groups. No differences in body mass index (BMI), age, and body weight were observed between the groups (p>0.05). Swimmers had greater LM and lean mass index (LMI), and lower total body fat mass percentage (FM%), fat mass index (FMI), and visceral adipose tissue (VAT) (p<0.01) compared to controls. BMD was similar in both groups regardless of sex (p>0.05). Male swimmers had lower FM% and FMI, and higher LM than female swimmers (p<0.001). BMD was correlated with BMI, LM, LMI, appendicular LMI (r=0.47, 0.55, 0.62, 0.60, respectively; p<0.001) and FM% (r=-0.35; p=0.04). Swimmers had higher lean and lower fat mass and VAT compared to inactive college students with similar age. Accordingly, swimming improves BC components; however, it does not seem to increase bone mineral density due to the reduced weight-bearing effect.