Base of Support (BoS) is defined as which of the following?

• A. Area of Body in Contact With the Supporting Surface
• B. Center of Mass
• C. Gravitational Constant
• D. Joint Range of Motion

Answer: (A)

The base of support is the area of the body that is in contact with the supporting surface. This region defines how far the projection of the center of mass can move before balance is lost, so a larger area (like with a wider stance or use of supports) generally provides more stability. In standing, the BoS is essentially the contact area between the feet and the surface; it can change with stance or devices.

The center of mass is a single point where the body's mass is considered to be concentrated, not an area. The gravitational constant is a universal value and not related to balance. Joint range of motion refers to how far joints can move, not where the body contacts the surface.