Relationship of Optical Density and Skinfold Measurements: Effects of Age and Level of Body Fatness

Abstract

We examined relationships between skinfold (SKF) and optical density (delta OD) measurements across age and levels of body fatness (%BF) for 151 women, 20 to 72 years. There were significant (p < .05) relationships between delta ODs and SKFs at all sites, except the thigh. The interaction (SKF x Age) was significant (p < .05) for pectoral and biceps delta ODs. Slope comparisons indicated the relationships for younger (29 years) and older (59 years) women differed significantly from zero and each other (p < .05). Analysis of SKF x %BF interactions revealed that relationships between SKFs and delta ODs at the pectoral and biceps sites for leaner (22% BF) women differed significantly from zero (p < .05) and were larger than those for obese (39% BF) women (p < or = .05). Thus, the relationship between SKFs and delta ODs is stronger for younger and leaner women compared to older and fatter women. These findings may reflect differences in fat layering due to age or body fatness and provide insight as to why the manufacturer's near-infrared (NIR) equation significantly underestimates the %BF of obese women.

Reliability and validity of body composition measures in female athletes

“…Limited research has been performed investigating the reliability of OD measures used with NIR. However, three studies have shown reliability for the biceps site to be very high at 0.95 (37), 0.96 (34), and 0.97 (13). These values are similar to those found in the present study.…”

Estimation of body composition of pigs by a near-infrared interactance probe technique

“…Human studies reported by WILMORE et al, (1994) indicated that only the NIR reading from the biceps contributed significantly to the variance in percent body fat as measured by hydrostatic weighing. Several other studies (CONWAY et al, 1984;HORTOBAGYI et al, 1991;MCLEAN and SKINNER, 1992;QUATROCHI et al, 1992;EATON et al, 1993) have reported that the inclusion of multiple site readings did not improve NIR results. The study by found that the NIR results systematically overestimated percent body fat in subjects with less than 20.7% body fat and underestimated percent body fat in subjects with more than 20.7% body fat.…”

Κινητική Δραστηριότητα Και Διατροφικές Συνήθειες Παιδιών Προεφηβικής Ηλικίας

“…Η μέθοδος δερματοπτυχών βασίζεται στο συλλογισμό ότι το υποδόριο λίπος έχει υψηλή συσχέτιση με το συνολικό σωματικό λίπος (Quatrochi et al, 1992). Αρχή αυτής της τεχνικής είναι ότι το ποσό του υποδόριου λίπους είναι ανάλογο με το 50% του συνολικού ποσού του σωματικού λίπους.…”