Center of Gravity and Base of Support

Introduction

• Balance maintenance is crucial for activities like walking, running, or standing.
• Balance depends on the relationship between the body's center of gravity (COG) and its base of support (BOS).

Center of Gravity (COG)

• Definition: A point where the body's mass is concentrated.
• Average Location: In front of lumbar vertebrae on the body midline when standing upright.
• Variability: Shifts based on body shape, posture, and position (e.g., bending forward or backward shifts COG).

Base of Support (BOS)

• Definition: Area or part of the body in contact with a supporting surface (e.g., ground, floor).
• Stability: Larger BOS provides more stability; smaller BOS requires precise balance.
• Examples:
  • Wider stance increases BOS, enhancing stability.
  • Narrow stance decreases BOS, making balance maintenance challenging.

Losing Balance

• Occurs when COG moves outside BOS.
• Results in either falling or adjusting (e.g., stepping forward) to expand BOS.

Low vs. High Center of Gravity

• Low COG: Increases stability and reduces risk of toppling.
• High COG: Decreases stability, increasing the risk of falling.

Low Center of Gravity: Sumo Wrestler

• Sumo wrestlers use a wide-legged stance to lower COG and increase BOS.
• This strategy enhances stability and makes them difficult to topple.

High Center of Gravity: Tiptoe Balancing

• When on tiptoes, COG is higher, leading to increased instability.
• Maintaining balance requires effort and control, demonstrating higher risk of falling compared to low COG positions.