Total body fat content in a group of professional football players

A hydrostatic weighing method coupled with a closed-circuit helium dilution technique was applied to twenty-nine professional football players of a successful Canadian Football team to obtain body density values. From these results, it was hoped that values for percent body fat could be calculated for each player using Siri's (1956) formula. Unfortunately, the values for body density were so high that for some players negative values for percent body fat were obtained. It has been suggested that these results reflect large skeletal deposits in response to the heavy exercise routines undertaken by the players. Skinfold measurements of the players suggest that there are more fat deposits than their body density values indicate. This casts serious doubt on the use of Siri's (1956) formula with the extremes of body form found in the population and also suggests restricted use of equations based on skinfold measurements for estimating body fat percent.