Standing, also referred to as orthostasis, is a position in which the body is held in an upright (orthostatic) position and supported only by the feet. Although seemingly static, the body rocks slightly back and forth from the ankle in the sagittal plane, which bisects the body into right and left sides. The sway of quiet standing is often likened to the motion of an inverted pendulum.[1]
Standing at attention is a military standing posture, as is stand at ease, but these terms are also used in military-style organisations and in some professions which involve standing, such as modeling. At ease refers to the classic military position of standing with legs slightly apart, not in as formal or regimented a pose as standing at attention. In modeling, model at ease refers to the model standing with one leg straight, with the majority of the weight on it, and the other leg tucked over and slightly around. There may be a time when a person is standing, where they lose control due to an external force or lack of energy, where they accelerate to the ground due to gravity. This is known as "falling" and may result in injuries around the part of the body that made contact with the ground.