article 2013 10 pages Sex-related differences and age of peak performance in breaststroke versus freestyle swimming Mathias Wolfrum, Beat Knechtle, Christoph Alexander Rüst, Thomas Rosemann, Romuald Lepers JournalBMC Sports Science, Medicine and RehabilitationDOI10.1186/2052-1847-5-29Populationelite men and women swimmers View on DOI ↗