Note to elite swimmers: Are you looking for a competitive edge in the hydrodynamics of your front crawl? Start by considering your stroke. If you are paddling, swimming with fingers pressed together like a blade, try spreading your fingers apart and rake the water for greater efficiency. The rake position of spread fingers increases the drag of the hand and reduces the slip velocity between the hand and the water. This diminishes the power dissipated for propulsion and as a result, increases your swimming efficiency.