Where is the human waist? Definitions, manual compared to scanner measurements

Abstract

Where exactly is the human waist? How do definitions work for women who deviate from the conventional body shape? Does the measuring instrument matter? Waist is conventionally understood to be a measurable zone within the abdominal region of the torso, a zone of considerable importance. There needs to be a good consistent waist definition, one accurate and valid for everyone. Incorrect definition and measurement will result in technical errors, commercial wastage and customer dissatisfaction. This paper investigates the waist’s location and size from the point of view of garment construction for 90 adult women scanned and manually measured in a breast reduction study at Flinders Medical Center, South Australia. There are differing definitions of the location of the human waist as well as different measuring instruments. This study compares:

• Two definitions:

• ISO 8559, 2.1.11 and

• CAESAR, Waist Circumference Preferred.

• Two different instruments:

• the traditional tape measure, and

• software-extracted computer-aided anthropometry (CAA). Substantial discrepancies between the results from these two locations-definitions were found. The choice of instrument used seriously affects the measurement obtained. This study demonstrates three things:

• waist is not horizontal for a significant sub group of the population,

• CAA extracted waist measurements are not accurate (same as real values) or valid (measures the characteristic) for a sub group, and

• manually measured CAESAR Preferred Waist accurately and validly measured all individuals studied. There is a clear need to modify ISO waist definition for garment construction to include the full range of anatomical variation encountered amongst women.