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This study determined the validity of previously published or newly derived equations to predict fat-free body mass (FFB) in high school wrestlers from the midwestern United States. Five laboratories participated in the data-pooling study (total sample of 860 subjects). Measures included body composition by underwater weighing and anthropometric measurements of body mass, stature, and selected circumferences, diameters, and skinfolds. Cross-validation of selected equations to predict FFB revealed the lowest levels of error from the equations of Lohman, Thorland et al., Katch and McArdle, and Behnke and Wilmore. Modification of the constants in these equations or generation of new equations did not substantially reduce prediction error. Overall, total error for these top equations ranged from 2.44 to 2.59 kg. However, based on observed trends, this error was of lower magnitude with the younger and lighter subjects and of higher magnitude with the older and heavier subjects. We conclude that these equations could be used singularly or collectively to determine FFB, and a minimal weight could then be derived and assigned to a scholastic wrestler.

Previous research by Tcheng and Tipton developed two prediction equations appropriate for the estimation of minimal weight for high school wrestlers. The purpose of this investigation was to cross-validate these equations using densitometric estimates of minimal weight. Skeletal dimension measurements and hydrostatic weighing were completed on 220 Iowa high school wrestlers at various times in and out of season. High concurrent validity (r = 0.93) and small residual errors (less than 0.33 kg) were observed when compared to densitometric estimates. Regression weights were of similar magnitude to those from the previous study. Two new prediction models were tested. Model II enhanced the multiple R over previous equations to 0.962 and decreased the SEE by 25% (0.55 kg). The equation was: Minimal Weight (lbs) = 0.49 x Current Weight (lbs) + 1.65 x Height (inches) + 1.81 x Chest Diameter (cm) + 6.70 x Right Wrist Diameter (cm) + 1.35 x Chest Depth (cm) - 156.56. It was concluded that the Tcheng-Tipton equations or the new models could be used as valid indicators of a minimal weight for scholastic wrestlers.

A longitudinal study was conducted with various members of the 1975 University of Iowa NCAA championship wrestling team to determine if excessive weight loss, accompanied by signs of dehydration, occurred at the college level of competition. Body weight changes from September to December indicated a mean loss of 6%, while skinfold totals (6 sites) changed from a mean of 58 mm to 37 mm. During a four-month period, mean weight losses of 10.2, 9.5, 8.0, 7.5 and 7.0 lbs occurred in intervals of 12, 4, 3, 2 and 1 day, respectively. Basal urines analyzed throughout the season usually contained 2-3 times the potassium excreted before the season started. Analyses of urines at various intervals during a 2-day time period prior to weigh-in showed a .003 increase in specific gravity, 160 mosm/1 increase in osmolarity, .10 decrease in pH, 45.3 mEq/1 decrease in Na+ concentration, and a 71.3 mEq/1 increase in K+ concentration which suggested that the wrestlers were dehydrated prior to competition. Total urinary electrolyte loss during the 2 days amounted to 3.7% of estimated total body Na+ stores and 3.0% of total body K+ stores. These data were similar to what had been reported for Iowa high school finalists and indicated that collegiate wrestlers were also competing while in a dehydrated state.

Many wrestlers lose a large amount of weight in a relatively short period of time to become certified for interscholastic competition. In most states, there are twelve certified weight classes with intervals ranging from 6 to 18 pounds. Using anthropometric data obtained from 834 "average" wrestlers that were measured 5-8 weeks before competition, we predicted their "minimal" body weights and assigned them into arbitrarily designated weight classes of 6, 8 and 10 pound intervals. In addition, the 1973-74 and the 1974-75 certifying records for Iowa wrestlers were examined with regard to frequency distribution patterns. The results indicated that the majority of students were certifying for a weight classes. In fast, forty percent of the more than 8900 students were certified for the 119-138 classes and 57% of the population were located within the 112-145 weight classes. Inspection of the frequency distribution patterns of wrestlers assigned to the arbitrary classes also showed a marked concentration of wrestlers who weighed between 120 and 140 pounds and this relationship became more apparent when ten pound intervals were considered. From these findings we recommended that state high school associations consider: 1) allowing more than one wrestler per team to compete in a single weight class; 2) porviding more weight classes than the current twelve; and 3) promoting body composition assessments during the pre-season period in order to minimize the problems created by the "making of weight."