Excerpt — ACSM's Body Composition Assessment With Web Resource

For the triceps, the subject is measured standing, with the arm hanging freely at her side. The measurer stands behind the subject and places the palm of his left hand on the subject’s arm above the mark, with the thumb and fingers directed inferiorly.

Systematic errors are measurement biases in one direction, which lead to measured values that are consistently higher or lower from the actual value.

Water is the most abundant component in the human body comprising about 60% of body mass in the reference man.