Which scenario demonstrates a child's center of mass is higher than in adults?

• A. Display a wide stance for balance
• B. Bend mostly from the ankles
• C. Keep feet narrow and bend from hips
• D. Lean backward with weight on the heels

Answer: (C)

Understanding how the center of mass changes with body position helps explain why this scenario shows a higher center of mass. The height of the center of mass depends on where most of the body's mass is located relative to the ground and how wide the base of support is. A higher center of mass occurs when the mass is held higher above the feet and the base of support is relatively narrow.

Keeping the feet close together creates a small base, and bending from the hips while keeping the trunk upright keeps much of the upper body mass higher above the ground. This combination puts the body's mass higher relative to the feet, illustrating a higher center of mass than in a position with a wider stance or with bending that lowers the torso.

In contrast, a wide stance lowers the center of mass by increasing the base of support, bending mostly from the ankles lowers the upper body toward the ground, and leaning backward with weight on the heels can shift the center of mass without necessarily raising it.