A number of investigators have been concerned with the anthropometric as well as physical characteristics of sumo wrestlers during the past several decades. However, none have attempted to determine body density and percent body fat by the most accurate technique of hydrostatic or underwater weighings. Thus, a precise quantification of body density and percent body fat for the wrestlers has not yet been obtained. Ogawa et al. (1972) have predicted the body composition of sumo wrestlers from a formula which added the triceps and subscapular skinfold thicknesses. As the regression equation used in this instance was based on samples of normal young men, it may not have great predictive accuracy when used on the exceptional population of very stout athletes.
The purposes of this study were : (1) to assess the validity of percent body fat estimation by skinfold thickness measurement when compared to the hydrostatic weighing criterion method ; (2) to determine the interrelationships between anthropometric variables for use in the clear assessment of the physical characteristics of ‘Shindeshi’ sumo wrestlers ; and (3) to thereby develop a formula that would reliably predict percent body fat using skinfold thicknesses and/or anthropometric measurements in this exceptional population. The interrelationships between anthropometric and body composition variables were investigated using 35 Shindeshi sumo wrestlers, aged 15-20 years (X=16.5±1.5) .
The results of the present study can be summarized as follows.
1. The Shindeshi in the present study possessed physiques more developed than those tested in the past, as evidenced by Rohrer's and Ponderal Indices which were approximately 180 and 26.2, respectively. The development of body weight was particularly notable (i.e., over 100kg) .
2. Percent body fat for the Shindeshi was remarkably higher than that of a normal population of the same age, with approximately seventy percent of the Shindeshi possessing more than 20% body fat and less than 1.05000 body density.
3. Body density and height correlated negatively and insignificantly with almost all the variables. In contrast, correlations of body weight, circumferences, and all other variables were, in most cases, high and positive, with body weight correlating least with height. The skinfold measurement correlating best with % body fat was that taken at the thigh site (r=0.898) . The circumference measurements correlating best with % body fat were obtained at the thigh (r=0.888 and 0.831) and the abdomen (r=0 885) parts.
4. Of the six formulae for estimating % body fat, Sloan's correlated best with % body fat as determined by densitometry, and best approximated the mean value of 24.5%. However, all of the equations underestimated the measured % body fat of the Shindeshi.
5. When an exceptional population is being investigated, estimation of % body fat should be done with a population specific equation to ensure predictive accuracy. The following multiple regression equation (r=0.963) should, therefore, be utilized for estimation of % body fat in sumo wrestlers.
Y=0.2488x1+0.6172x2-14.3962 where x1 and x2 are abdomen circumference and skinfold thickness at thigh, respectively.
