Centre of Gravity and Centre of Buoyancy distribution in a swimmer: what is the practical implication?

• A. It helps align natural stability and balance in water.
• B. It means buoyant force acts at the hips.
• C. It means gravity and buoyancy cancel out.
• D. It causes equal forces at all depths.

Answer: (A)

The practical idea is how the weight line (centre of gravity) and the upward buoyant line (centre of buoyancy) interact to affect stability in water. The buoyant force acts through the centre of buoyancy and shifts with body orientation, while gravity acts through the centre of gravity. When the swimmer tilts, these lines don’t align, creating a turning moment. If that moment tends to push the body back toward a balanced, streamlined position, the swimmer has natural stability and easier control in the water. This is why coaching emphasizes a horizontal, aligned posture so the centres of buoyancy and gravity support stable balance rather than disrupt it. The buoyant force isn’t fixed at the hips, forces don’t cancel out in normal swimming, and buoyancy depends on how much of the body is submerged, not depth alone.