HOW THE TEST WAS CONDUCTED

The test positioned a neutrally buoyant test diver just below the surface of the water. Readings in which the diver’s fin broke the surface or the diver sank below the test range were disqualified. Given the human variable, there was no way the study could be perfectly uniform and consistent, but the diver was first asked to kick gently using about 4-5 kg. of thrust and then to fin as hard as he could for several seconds to get a maximum thrust. Thrust was measured with a spring balance connected to the diver by a line and pulley, and the test diver was given a break between each pair of fins he tested. Two or three different pairs of fins of each brand were tested to try to take manufacturing variances into account, and models were retested at different times throughout the day to factor in fatigue.