Clark R Randall, Sullivan Jude C, Bartok Cynthia J, Carrel Aaron L
University of Wisconsin Hospital Sports Medicine Center, University of Wisconsin, Madison, WI 53711, USA.
Med Sci Sports Exerc. 2007 Nov;39(11):2069-75. doi: 10.1249/mss.0b013e31814fb423.
To cross-validate the DXA prediction of minimum weight (MW) in high school wrestlers, using a criterion-referenced analysis. The goal was to independently evaluate whether DXA provided a MW within acceptable limits for the sport of wrestling. Secondarily, the DXA prediction error was compared against the currently approved skinfold (SF) method.
Criterion MW was calculated by hydrostatic weighing (HW) with measured residual lung volume. Whole-body scans were performed with a Norland XR-36 bone densitometer. All skinfolds were taken by the same experienced measurer. The subject's body density was computed by Lohman and was converted to percent body fat, using the equation of Brozek et al. The measured fat-free mass was used to calculate each wrestler's MW at 7% body fat. Subjects were 94 Wisconsin high school wrestlers (mean (SD): age = 15.1 yr (1.2), height = 170.3 cm (7.1), weight = 63.2 kg (9.6).
There was no significant difference in mean MW from DXA (60.6 kg (9.0)) and the HW criterion (59.8 kg (9.0)). The correlation was strong (r = 0.98), and the regression for the relationship between HW and DXA (y = 0.976 x DXA + 0.698 kg) did not significantly deviate from the line of identity. A low standard error of estimate (SEE) of 1.7 kg and a pure error (PE) of 1.9 kg were found, with residuals ranging from -3.94 to 2.88 kg. This PE was similar to the SF method (2.1 kg) in the sample. Bland-Altman analysis showed no systematic bias in the prediction of MW across weight classes.
We conclude that DXA provided a valid prediction of MW in this sample of high school wrestlers.
采用标准参照分析方法对双能X线吸收法（DXA）预测高中摔跤运动员最低体重（MW）的结果进行交叉验证。目标是独立评估DXA预测的MW是否在摔跤运动可接受的范围内。其次，将DXA预测误差与目前认可的皮褶厚度（SF）法进行比较。
通过水下称重（HW）并测量残气量来计算标准MW。使用Norland XR - 36骨密度仪进行全身扫描。所有皮褶厚度均由同一位经验丰富的测量人员测量。采用Lohman公式计算受试者的身体密度，并使用Brozek等人的公式将其转换为体脂百分比。用测得的去脂体重计算每位摔跤运动员在体脂率为7%时的MW。受试者为94名威斯康星州高中摔跤运动员（均值（标准差）：年龄 = 15.1岁（1.2），身高 = 170.3厘米（7.1），体重 = 63.2千克（9.6））。
DXA预测的平均MW（60.6千克（9.0））与HW标准值（59.8千克（9.0））之间无显著差异。相关性很强（r = 0.98），HW与DXA之间关系的回归方程（y = 0.976×DXA + 0.698千克）与恒等线无显著偏差。估计标准误差（SEE）为1.7千克，纯误差（PE）为1.9千克，残差范围为 - 3.94至2.88千克。该样本中的此PE与SF法（2.1千克）相似。Bland - Altman分析表明，不同体重级别的MW预测无系统偏差。
我们得出结论，DXA能够有效预测该样本中高中摔跤运动员的MW。
