title: New equations improve NIR prediction of body fat among high school wrestlers.
abstract: METHODS
  Methodologic study to derive prediction equations for percent body fat (%BF).
  
  
  OBJECTIVE
  To develop valid regression equations using NIR to assess body composition among high school wrestlers.
  
  
  BACKGROUND
  Clinicians need a portable, fast, and simple field method for assessing body composition among wrestlers. Near-infrared photospectrometry (NIR) meets these criteria, but its efficacy has been challenged.
  
  
  METHODS
  Subjects were 150 high school wrestlers from 2 Midwestern states with mean +/- SD age of 16.3 +/- 1.1 yrs, weight of 69.5 +/- 11.7 kg, and height of 174.4 +/- 7.0 cm. Relative body fatness (%BF) determined from hydrostatic weighing was the criterion measure, and NIR optical density (OD) measurements at multiple sites, plus height, weight, and body mass index (BMI) were the predictor variables.
  
  
  RESULTS
  Four equations were developed with multiple R2s that varied from .530 to .693, root mean squared errors varied from 2.8% BF to 3.4% BF, and prediction errors varied from 2.9% BF to 3.1% BF. The best equation used OD measurements at the biceps, triceps, and thigh sites, BMI, and age. The root mean squared error and prediction error for all 4 equations were equal to or smaller than for a skinfold equation commonly used with wrestlers.
  
  
  CONCLUSIONS
  The results substantiate the validity of NIR for predicting % BF among high school wrestlers. Cross-validation of these equations is warranted.
authors.affiliation: Physical Therapy Graduate Program, The University of Iowa, Iowa City 52242-1997, USA. bob-oppliger@uiowa.edu
authors.forename: R A
authors.initials: RA
authors.lastname: Oppliger
authors.forename: R R
authors.initials: RR
authors.lastname: Clark
authors.forename: D H
authors.initials: DH
authors.lastname: Nielsen
mesh_terms: D000273:Adipose Tissue; D000293:Adolescent; D015982:Bias; D001823:Body Composition; D001827:Body Height; D001835:Body Weight; D017097:Electric Impedance; D006801:Humans; D016014:Linear Models; D055095:Optics and Photonics; D011237:Predictive Value of Tests; D012885:Skinfold Thickness; D019265:Spectroscopy, Near-Infrared / Q000379:methods* / Q000592:standards*; D014952:Wrestling