Showing papers by "Andrew S. Jackson published in 1977"

Prediction accuracy of body density, lean body weight, and total body volume equations.

Abstract: The purpose of this study was to determine the accuracy of percent fat estimates derived from regression equations with functions of predicting body density (BD), lean body weight (LBW), and total body volume (TBV) from anthropometric variables. BD, LBW, and TBV equations were derived from the data of 95 young, adult men (percent fat X = 13.4%). The multiple correlations for these equations were: BD, 0.86-0.83; LBW, 0.96-0.95; and TBV, 0.99. The zero order correlations between laboratory determined percent fat and percent fat derived by the BD, LBW, and TBV equations ranged from 0.80 to 0.86 with standard errors from 3.1% to 3.7%. This shows that BD, LBW, and TBV equations have similar accuracy when transformed to percent fat. The derived equations were cross validated with three additional, but diverse, samples (percent fat X = 5.1%; 16.7%; 27.1%). The cross validations results revealed that all equations exhibited similar accuracy. With samples differing in percent fat, systematic prediction errors occurred. The results further confirm population specificity of prediction equations.

Body composition of elite class distance runners

Abstract: The percent fat in distance runners has been estimated at 6% to 8%.'-5 Costill, Bowers, and Kammer,% however, have suggested that top quality marathon runners probably have lower values. Limitations in previous investigations that could affect the accuracy of body density (BD) estimation resulted from the researchers' not differentiating distance runners from sprinters or field event athletes, not including elite runners (or mixing elite and average runners in the sample), and not using an accurate laboratory technique for determining percent Thus, a precise quantification of BD and percent fat of elite distance runners is needed. Preliminary results from an investigation on an Olympic gold medal winner (marathon) showed leaner values if BD was measured by the hydrostatic weighing technique rather than by prediction equations using various combinations of anthropometric measures. Forsyth and Sinning concluded that existing prediction equations estimating BD from various combinations of skinfold fat ( S ) , girth (G), and diameter (D) measurements accurately predicted the BD of young sedentary men and athletes, but that the equations might not be valid for a very lean athlete. Likewise, the use of regression equations developed from samples of young men and women systematically resulted in an overestimation of BD for middle-aged men and this difference was thought to reflect the significantly greater amount of fat found in the middle-aged population. These findings supported the practice of using population-specific equations and questioned the accuracy of predicting BD in a very lean population from equations developed from a normal and/or athletic population with a different body type. The purpose of this investigation was to measure and predict BD in national and international class distance runners. The questions considered were twofold: what is the BD of elite runners? and can BD of elite runners be estimated accurately with regression equations using anthropometric variables?

The effects of training and position on judges' ratings of a gymnastic event.

Abstract: The purpose of this study was to determine the effects of training and position on judges' ratings of a gymnastic event. Twenty-four women judged the performance of the squat vault by 40 college women. The judges were divided into four groups. Two groups received written training, and two groups, extensive training. After completing their training, one written group and one extensive group viewed the performances from the side of the vaulting box; the other two groups viewed from the front of the vaulting box. Judge position and judge training were found to have significant effects upon judges' ratings. Significantly lower ratings were given by the judges who viewed the vault from the front and had received extensive training.