Over the years, we’ve observed hundreds of Olympic swimmers underwater and we’ve noticed they almost all have at least one thing in common, releasing air bubbles under the chest. In this video we measured the effect of those bubbles on reducing frontal drag. You won’t believe the results!


  1. This is great! Presumably the same would apply on the start and for push off? Did you have the chance to experiment with the effect of varying the volumes of exhalation – better to err on releasing slightly more or slightly less air? Thanks again for all the wonderful analysis!

    1. Yes! That is correct. We did not vary the volume of exhalation but keep in mind that the exhale is quick and the inhale even quicker for swimmers. It is an air exchange, not a deep breath.