Body composition is a key consideration in the physical make-up of professional soccer players. The aims of the present study were to determine whether the body composition of professional soccer players varied according to playing position, international status or ethnicity, and to establish which variables best distinguished the soccer players from a reference group. Body composition was assessed using dual-energy X-ray absorptiometry in 64 male professional soccer players. Measured variables included bone mineral density and the relative amounts of lean and fat mass. Data were analysed using analysis of variance and stepwise discriminant function. The soccer players recorded better values than a reference group (n = 24) for all body composition compartments. Percent lean mass and bone mineral density were the variables best able to identify the soccer players (95.5% correctly classified). Differences in body composition were evident between goalkeepers and outfield players, but not between outfield playing positions. No differences were found on the basis of international status. The non-Caucasian players demonstrated significantly lower percent body fat (9.2 +/- 2.0%) than the Caucasian players (10.7 +/- 1.8%). It was concluded that body composition is important for elite soccer players, but that homogeneity between players at top professional clubs results in little variation between individuals.

The use of generic equations for estimating percent body fat from skinfold thicknesses can be criticised when applied to specific sports. The present aims were to compare existing methods of using skinfold data and to derive an equation for predicting body fat values in professional soccer players. Forty-five professional soccer players (24.2 +/- 5.0 years; 82.0 +/- 8.5 kg; 1.82 +/- 0.07 m) participated. Skinfold thicknesses were assessed at eight sites for the application of existing prediction equations. Skinfold data were also utilised to determine a novel soccer-specific equation. All players had a reference estimate of percent fat by dual-energy x-ray absorptiometry (DXA). The existing skinfold equations differed from the DXA-referenced values by varying degrees, the equation of Withers et al. (1987) demonstrating the lowest bias and highest relationship and agreement with DXA. Regression analysis resulted in an equation incorporating anterior thigh, abdominal, triceps and medial calf sites, accounting for 78.4% variance in DXA criterion values.

Wheelchair users undergo changes in body composition as a result of disability. In this study the distribution of bone mineral, lean and fat mass was assessed in highly-trained female wheelchair athletes and a reference group by dual-energy X-ray absorptiometry (DXA). The transferability of anthropometric equations commonly used in female groups was examined in order to establish a suitable field method of body composition assessment. The DXA total-body results indicated no difference between groups, but segmental analyses uncovered regional differences. The wheelchair athletes had greater BMD (p=0.088), more lean mass (p<0.001) and a lower percent fat (p=0.050) in their arms. The reverse was true of the legs (p< or =0.001). The trunk as a whole did not differ between groups. In general, the anthropometric equations showed a lack of transferability to the wheelchair group and tended to underestimate total percent body fat. Anthropometric measures such as body mass index (BMI) and waist girth showed strong correlations with body fat in the wheelchair group (BMI: r=0.90, p=0.001; waist: r=0.83, p=0.001), but weaker results in the reference group. It is recommended that specific anthropometric equations be developed for use in the absence of a 'gold standard' measure of body composition such as DXA.

The acquisition of soft tissue measurements, fat (chemical) or adipose tissue (morphological) quantities, is essential in clinical research and nutritional status and its associated health risks. This has led to a proliferation of methods for the in-vivo determination of body composition. None of the indirect in-vivo approaches to estimate body adipose tissue has been validated against direct dissection data except for the skinfold.Since the development of DEXA as a measurement tool of bone density and mineral content for the detection of osteoporosis, it became a tool for measuring regional and whole body masses, lean tissue, and fat. A number of validation attempts have been made, however mostly against other indirect in-vivo techniques.The purpose of this study was to conduct an in-vitro validation and quality control of the data acquisition of DEXA using dissection as the criterion method. Fourteen porcine hind legs were scanned with DEXA, weighed in air and water and dissected into skin, adipose tissue, muscle and bone. Normal distribution, means, standard deviations, paired student t-test, Pearson correlation coefficients, interclass correlations test, and a Bland-Altman plot were used. The results show systematically good to excellent correlations between DEXA and dissection data acquisition (r 2 ϭ0.75 to 0.99), but absolute indirect DEXA and direct dissection values are significantly different ( pϽ0.05). DEXA overestimates total weight, lean mass, and fat free mass and underestimates both mass and % adipose tissue.DEXA provides erroneous values for bone density. Data produced by DEXA are morphological, not chemical values, as claimed by the manufacturer.This 'pilot' study indicates that a 'simple' combination of skin, adipose tissue, muscle, and bone from hind legs may give an incomplete picture of reality as one needs to measure viscera, connective tissue, and air pockets of the body. Validation studies with intact bodies are advised.

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