skinfold

A skinfold is a fold of skin and the underlying subcutaneous fat. In body composition assessment, skinfold measurements estimate body fat percentage by measuring the thickness of subcutaneous fat at standardized sites using calipers.

Procedures are performed by trained personnel who pinch a double layer of skin and fat, lift it away from the underlying muscle, and place the caliper perpendicular to the skinfold to obtain a thickness reading in millimeters. Readings are typically repeated two or three times at each site and averaged. Common sites include the triceps, subscapular, suprailiac, chest, abdomen, and thigh; multi-site protocols may use three, four, or seven sites.

Calculations convert the sum of skinfold thicknesses into an estimate of body density and fat percentage using regression equations derived from reference populations. Examples of widely used approaches include three-, four-, or seven-site models.

Uses and limitations: Skinfold assessment is inexpensive, portable, and widely used in fitness testing, sports science, and clinical settings for tracking changes in body fat over time. Accuracy depends on examiner skill and proper technique. Differences in fat distribution by sex, age, and ethnicity, along with hydration status and recent exercise, can affect results. The method is less reliable for very lean or very obese individuals and may be unsuitable for certain populations.

History: The skinfold technique was developed in the mid-20th century as a practical approach to estimating adiposity before more direct measures were available.