Use Explosive Breathing For Better Buoyancy

Air is less dense than water. As a result, your students are more buoyant when there's air in their lungs. This suggests that your sinkers can actually improve their buoyancy by changing their breathing pattern.

Use Explosive Breathing for Better Buoyancy

To become more buoyant, your sinkers should use "explosive breathing" as opposed to "trickle breathing." In other words, rather than releasing air gradually, they should hold their breath as long as possible and blow out explosively.

This breathing pattern keeps air in the lungs for most of each stroke, which keeps them higher in the water.