Hydrostatic Weighing is the most common assessment used to
test for body composition in exercise physiology laboratories. A person’s normal
weight is compared with their weight measured by being underwater. Comparing
these two weights can determine a person’s body fat percentage because fat
floats and muscle sinks. Due to the amount of time this test takes, as well as
the skill, space, and equipment needed to do this procedure, it is not used
often. The standard error of estimate is 0.5%.