The editor of the wonderful Daily News of Open Water Swimming sent me a copy of the Open Water Swimming Almanac from the 2010 Global Open Water Swimming Conference. One of the chapters in the almanac asks the question: How far is a marathon swim?
I said in a previous post that I believed the 10KM swim was considered a marathon swim due to the time it takes for relatively in-shape swimmers and runners to complete their respective marathons. And in the almanac, the authors support this:
A 10K swim done by a world-class swimmer is comparable in time to a marathon run done by a world-class marathon runner. Male world-class swimmers (i.e., the top 25 swimmers in the world) can complete a 10K swim in about an hour and 55 minutes while female world-class swimmers can complete 10K swims in right around 2 hours in relatively calm waters without currents or waves. Male world-class runners are generally under 2:10 and women under 2:25 under favorable conditions.
Interestingly, the authors point out that the land-based marathon was not standardized to its current length (26.2 miles) until 1921. Various distances were debated for years before 1921.
With the 10K-length marathon swim now an Olympic event, there is hope among the open water swimming community that sooner rather than later a consensus on the definition of marathon swim will be arrived upon. Neither the U.S. Masters Swimming nor the USA Swimming organizations define the term, although FINA (Fédération Internationale de Natation) does consider 10 kilometers as the distance of a marathon swim.