Hydrodynamic Principles

Buoyancy is the upward force that water places on an object when the object is in water. Water’s buoyancy opposes gravity’s downward force, which has the effect of lessening body weight in the water.

Buoyancy is also the reason that many people who have mobility impairments on land find it much easier to move in the water, because the buoyancy of the water helps to support the person’s body weight. Buoyancy allows swimmers to spend most of their energy producing forward movement rather than supporting themselves.

 

Evaluating Your Natural Buoyancy

  1. Move into a tuck position. Hold your knees against your chest until your body stops rising or sinking. Recover to a standing position.

    Did your back rise above the surface? If so, you oat easily.

     

  2. Take a large breath of air, hold it and return to the tuck oat position. Recover to a standing position.

    Did your back rise above the surface this time? If so, you have some dif culty oating and when oating on your back, you probably oat more in a diagonal position than a horizontal one.

     

  3. Take a large breath of air, return to the tuck oat position, then slowly let the air out through your mouth and nose. Recover to a standing position.

    Did your body drift down as you exhaled? If so, you do not oat easily and are likely to sink while trying to oat motionlessly.

    Move into a back float with your arms at your sides. Recover to a standing position.

    Did your body remain mostly horizontal in the water? If so, you float easily.

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