JT Lightfoot, DJ Torok, BL Marks. Near infrared interactance does not accurately measure body fat in field conditions . Southeastern Regional American College of Sports Medicine, Lexington, KY, Feb. 2-4, 1995.
Several studies have shown that near infrared interactance (NIR) does not accurately estimate body fat percentage under strict laboratory conditions. However, NIR is used quite frequently in field situations instead of other field measurements such as skinfolds (SF) and circumference measurements (CM). The purpose of this study was to determine if the NIR exhibited any relationship to body fat measurements derived using SF and CM. Data from 114 subjects (65 females, 49 males; 24±1 yrs; 68.8±1.4 kg; 169.7±1.2 cm) in six college activity classes where body fat percentages were determined using all three methods was retrospectively analyzed. SF were taken at 3 gender-specific sites and bodyfat percentages calculated using accepted formulas (Jackson & Pollock, 1985). In the males, lower abdominal CM and weight were used and in the women, hip CM and height were used to determine bodyfat percentage (Wilmore, 1988). NIR resulted in significantly (p<0.05) higher bodyfat percentages (25.4±0.5%) than sf (18.6±0.7%) and cm (19.6±0.8%). nir body fat estimates were 70% higher than sf for the males and 21% higher for the females. there was a significant correlation between the nir and sf readings (y="14.1+0.61x;" r="0.81)" and between the nir and cm (y="15.47+0.50x;" r="0.76)." furthermore, sf and cm readings were significantly related (y="4.64+0.71x;" r="0.80)." our data indicate that while nir will track sf and cm readings during field conditions, it does not give accurate estimations of body fat percentage as determined using either sf or cm.