What is the primary component assessed by hydrostatic weighing?

Hydrostatic weighing is a method used to determine body composition, primarily by assessing body density. The principle behind this technique is based on Archimedes' principle, which states that an object's buoyancy when submerged in water can be used to calculate its density.

The primary component assessed through hydrostatic weighing is fat mass. This is accomplished by measuring the volume of water displaced when a person is submerged. From this, body density is calculated, which allows for the estimation of body fat percentage. Fat mass is less dense than water, so individuals with a higher proportion of body fat will displace less water compared to those with more lean body mass. Therefore, hydrostatic weighing is particularly effective in estimating fat mass as it provides insights into the proportion of fat versus lean tissues in the body.

This method does not directly assess components like bone mass, lean body mass, or muscle mass; rather, it derives these through calculations related to body density and the overall proportion of fat and lean components within the body.