One of many things freedivers need to master is the equalisation that is required throughout the descent. Often it is the inability to equalise that prevents freedivers from reaching their goals.

Sara had George and Stuart concentrating on their mouth-fill techniques. The Blue Eye FX film crew was well amused filming champion freedivers with straws in their mouths while holding their noses! But it worked! Both George and Stuart had improved their depths at the end of three days training.
Check out Splash on The Underwater Channel to see Sara at school.