Analysis of swimming performance in FINA World Cup long-distance open water races

Conclusion
Female long-distance swimmers competing in FINA World Cup races between 2000 and 2012 improved in 10 km but impaired in 5 and 25 km, whereas men only impaired in 5 km. The age of peak performance was younger in women (approximately 23 years) compared to men (about 25–27 years).

Source: Extreme Physiology and Medicine - January 2, 2014 Category: Physiology Source Type: research