Smith D B, Johnson G O, Stout J R, Housh T J, Housh D J, Evetovich T K
University of Nebraska-Lincoln, 68588-0229, USA.
Int J Sports Med. 1997 Oct;18(7):531-7. doi: 10.1055/s-2007-972677.
The present investigation examined the validity of near-infrared interactance (NIR) estimates of relative body fat (% fat) from the Futrex-5000 (F5000), Futrex-5000A (F5000 A), and Futrex-1000 (F1000) instruments. Ninety-eight female high school gymnasts (X age+/-SD = 15.7+/-1.2 yr) participated in this investigation. Subsamples were used to cross-validate the F5000 (n = 52), F5000A (n = 46), and F1000 (n = 89) instruments. The NIR % fat estimates were validated against criterion % fat from underwater weighing (UWW) using the adult conversion constants of Brozek et al. (6) (UWWB) and the female age-specific constants of Lohman (23) (UWWL). The cross-validation statistical analysis included examination of the constant error (CE), standard error of estimate (SEE), r, and total error (TE). In addition, full-model multiple regression analyses were used to predict UWWB or UWWL from body weight (BW) and height (HT). BW and HT were correlated with % fat at R = 0.65-0.70, while the validity coefficients for the NIR instruments ranged from r = 0.40-0.78. The F5000 resulted in nonsignificant CE values (-0.3 % fat vs UWWB and 1.5 % fat vs UWWL; p > 0.008) as well as the lowest TE values (TE = 3.1 % fat vs UWWB and 4.0 % fat vs UWWL). All other NIR estimates of % fat resulted in TE values > or = 6.3 % fat. In addition, for all NIR instruments there were negative correlations for the plots of the CE versus the mean of predicted and criterion (UWWB and UWWL) % fat. Therefore, the present findings indicated that the F5000 provided more accurate estimates of % fat than the F5000A or F1000 instruments, but may underestimate the desired minimal body weight for female gymnasts at the low end of the % fat distribution.
本研究检验了Futrex-5000（F5000）、Futrex-5000A（F5000A）和Futrex-1000（F1000）仪器通过近红外相互作用（NIR）估算相对体脂（%脂肪）的有效性。98名高中女子体操运动员（年龄X±标准差=15.7±1.2岁）参与了本研究。子样本用于对F5000（n = 52）、F5000A（n = 46）和F1000（n = 89）仪器进行交叉验证。使用Brozek等人（6）的成人转换常数（UWWB）和Lohman（23）的女性特定年龄常数（UWWL），将NIR%脂肪估算值与水下称重（UWW）得出的标准%脂肪进行验证。交叉验证统计分析包括对恒定误差（CE）、估计标准误差（SEE）、r和总误差（TE）的检验。此外，使用全模型多元回归分析，根据体重（BW）和身高（HT）预测UWWB或UWWL。BW和HT与%脂肪的相关系数R = 0.65 - 0.70，而NIR仪器的有效性系数范围为r = 0.40 - 0.78。F5000得出的CE值不显著（与UWWB相比为-0.3%脂肪，与UWWL相比为1.5%脂肪；p>0.008），且TE值最低（与UWWB相比TE = 3.1%脂肪，与UWWL相比TE = 4.0%脂肪）。所有其他NIR%脂肪估算值的TE值≥6.3%脂肪。此外，对于所有NIR仪器，CE与预测和标准（UWWB和UWWL）%脂肪均值的关系图均呈负相关。因此，本研究结果表明，F5000比F5000A或F1000仪器能更准确地估算%脂肪，但在%脂肪分布低端可能会低估女子体操运动员所需的最低体重。
