Clark R Randall, Bartok Cynthia, Sullivan Jude C, Schoeller Dale A
University of Wisconsin Hospital Sports Medicine Center, University of Wisconsin, Madison, WI 53711, USA.
Med Sci Sports Exerc. 2005 Jun;37(6):1061-8.
The National Collegiate Athletic Association (NCAA) and several state associations require prediction of minimum weight (MW) for collegiate and high school wrestlers. The rule requires assessment of body composition before the competitive season to minimize unhealthy weight-loss practices. Leg-to-leg bioelectrical impedance analysis (BIA) has been suggested for use with wrestlers.
To evaluate leg-to-leg BIA against a four-component (4C) criterion to determine whether leg-to-leg BIA predicted MW within acceptable limits for the sport of wrestling.
Criterion MW was calculated by the 4C equation of Lohman (19) using independent measurement of body density (BD) by hydrostatic weighing, bone mineral content (BMC) by dual x-ray absorptiometry (DXA), and total body water (TBW) by deuterium dilution. Subjects were 57 wrestlers (mean +/- SD; age = 19.7 +/- 1.3 yr, height = 176.6 +/- 7.3 cm, weight = 77.7 +/- 12.4 kg). Hydration was confirmed by the NCAA guidelines. Accuracy, precision, and systematic bias were examined.
Comparable mean values (72.2 +/- 9.7 vs 72.2 +/- 10.3 kg), a high correlation (r = 0.94), and a regression line similar to the line of identity were found between BIA and 4C. However, large individual differences and systematic bias were seen across the range of MW. BIA predicted MW within 3.5 kg 68% of the time and within 7.0 kg 95% of the time. MW residuals ranged from -10.4 kg to +6.9 kg. When using 2.0 kg as an acceptable cutoff for error, only 40% of the BIA values were within 2.0 kg of the criterion.
Large individual variation was seen, and, by definition, the precision was poor when estimating MW for individuals. In practical terms, the prediction error may span multiple weight classes, thus making leg-to-leg BIA unacceptable for prediction of MW in this sample under the conditions of the study.
美国国家大学生体育协会（NCAA）和几个州协会要求预测大学和高中摔跤运动员的最低体重（MW）。该规则要求在比赛季节前评估身体成分，以尽量减少不健康的减肥行为。有人建议将双腿生物电阻抗分析（BIA）用于摔跤运动员。
根据四成分（4C）标准评估双腿BIA，以确定双腿BIA预测的MW是否在摔跤运动可接受的范围内。
使用Lohman（19）的4C方程计算标准MW，该方程通过静水称重独立测量身体密度（BD）、通过双能X线吸收法（DXA）测量骨矿物质含量（BMC）以及通过氘稀释法测量总体水（TBW）。受试者为57名摔跤运动员（平均±标准差；年龄=19.7±1.3岁，身高=176.6±7.3厘米，体重=77.7±12.4千克）。根据NCAA指南确认水合状态。检查了准确性、精密度和系统偏差。
BIA与4C之间发现了可比的平均值（72.2±9.7对72.2±10.3千克）、高度相关性（r=0.94）以及与恒等线相似的回归线。然而，在MW范围内观察到了较大的个体差异和系统偏差。BIA在68%的时间内预测的MW在3.5千克以内，在95%的时间内预测的MW在7.0千克以内。MW残差范围为-10.4千克至+6.9千克。当使用2.0千克作为可接受的误差临界值时，只有40%的BIA值在标准值的2.0千克以内。
观察到较大的个体差异，并且根据定义，在估计个体的MW时精密度较差。实际上，预测误差可能跨越多个体重级别，因此在本研究条件下，双腿BIA对于该样本中MW的预测是不可接受的。
