Although the riblets improved the flexible foil’s swimming speed by 7.2 percent, the Speedo fabric apparently had no effect at all, perhaps because its bumps were small, rounded and very widely spaced compared with both shark denticles and the sharp-edged riblets. (Lauder did note that figure-hugging Fastskin swimming costumes probably enhance the swimmer’s performance in other ways.)
Read more here on the Huffington Post