Near Infrared Reactance for the Estimation of Body Fatness in Regularly Exercising Individuals

J. Evans; M. I. Lambert; L. K. Micklesfield; J. H. Goedecke; C. L. Jennings; L. Savides; A. Claassen; E. V. Lambert

doi:10.1055/s-0032-1331716

International Journal of Sports Medicine, Table of Contents

Int J Sports Med 2013; 34(07): 612-615
DOI: 10.1055/s-0032-1331716

Training & Testing

Near Infrared Reactance for the Estimation of Body Fatness in Regularly Exercising Individuals

J. Evans

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

,

M. I. Lambert

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

,

L. K. Micklesfield

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

²WITS/MRC Developmental Pathways for Health Research Unit, Department of Pediatrics, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa

,

J. H. Goedecke

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

³South African Medical Research Council, Parow, Cape Town, South Africa

,

C. L. Jennings

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

,

L. Savides

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

,

A. Claassen

⁴Virgin Life Care (Pty) Ltd, Cape Town, South Africa

,

E. V. Lambert

¹UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, South Africa

› Author Affiliations

Abstract

Near infrared reactance (NIR) is used to measure body fat percentage (BF%), but there is little data on its use in non-obese, regularly exercising individuals. Therefore, this study aimed to examine the limits of agreement between NIR compared to dual x-ray absorptiometry (DXA) for the measurement of BF% in 2 cohorts of regularly exercising individuals. BF% was measured using DXA and NIR in a regular exercising (≥3 sessions/week), healthy active cohort (HA; n=57), and in a regularly exercising and resistance trained (≥2 sessions/week) cohort (RT; n=59). The RT cohort had lower BF% than the HA cohort (15.3±5.5% and 25.8±7.1%, P<0.001). In the HA and RT cohorts, NIR BF% was associated with DXA BF% (R²=0.72, SEE=3.7, p<0.001 and R²=0.50, SEE=4.1 p<0.001, respectively). In the HA cohort, NIR tended to under-predict BF% (mean difference: − 1.3%; 95% limits of agreement (LOA); − 8.8 to 6.2%) whereas in the RT cohort, NIR tended to over-predict BF% compared to DXA (mean difference: 1.1; 95% LOA; − 8.1 to 10.3%). In conclusion, NIR and DXA yield similar average BF% measurements in 2 cohorts of non-obese regularly exercising individuals. However, the rather broad LOA of NIR need to be considered when using NIR to screen for overweight and obesity, or measure and track changes in body composition.

Key words

body composition - resistance training - NIR - DXA

Full Text

References

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