Validity and Reliability of Skinfold Calipers
As skinfold calipers are quick, easy-to-use, and very affordable for estimating body fat percentage, they have become more widely used over the years (Wells, 2005). This has happened despite newer techniques such as dual-energy x-ray absorptiometry (DEXA), magnetic resonance imaging (MRI), computerized tomography (CT), and bioelectrical impedance analysis (BIA) all having been developed (Wang et al., 2006).
One study in 2005 by Eston et al (2005) investigated the relationship between body fat percentage, measured by skinfolds, versus DEXA, and found that skinfolds were “highly related to the percent body fat in fit and healthy young men and women”; especially the thigh skinfold, which showed the highest correlation with total percent fat.
Another study evaluating the validity of body fat measured by skinfolds, ultrasound, and BIA compared to DEXA, found that in 208 young men and women, skinfolds were highly correlated to DEXA results (r = 0.91-0.92), with a mean difference between both measures of 6.9 ± 0.4 percent body fat (Duz, Kocak, & Korkusuz, 2009). Furthermore, skinfolds tended to underpredict body fat percentage as compared to DEXA, revealing that DEXA and skinfold could not be used interchangeably. According to this study, and others (Duz et al., 2009; Lean, M., Han, S, Deurenberg, 1996), skinfolds may have a significant bias at extremes of body fat and age.
The best use of skinfolds seems to be their raw values (i.e. the summation of all measurement sites in millimetres), rather than their ability to predict total body fat percentage because there are errors associated with the accuracy of the collection of the raw data, and error in assumptions in the final values (Wells, 2005). Raw skinfold data can give us a good idea of the regional fatness, unlike other measures like BMI or circumference measures alone (Jackson, Pollock, Graves, & Mahar, 1988; Wells, 2005).
For some populations, such as athletic populations, where the difference of one percentage point of body fat can make a difference in performance, skinfolds are likely more important (Ransdell & Murray, 2011). For overweight or obese populations, taking skinfolds may be of less use, as accuracy and reliability of the skinfold measurements will be harder to repeat as the skinfold thickness increases, so methods like DEXA may be more accurate (Donini et al., 2013). Other studies, for example on obese children, have found good agreeance between skinfolds and percent fat measured by DEXA (Wohlfahrt-Veje et al., 2014), however, considerations based on the population being measured must be addressed by each case separately.