Here[1] is the link to the original article, which shows sources.
Here[2] is an article in Runner's World which discusses some studies and provides more links to balance the story.
tldr; The headline of the article is sensationalized.
[1] http://articles.elitefts.com/training-articles/women-running...
[2] http://www.runnersworld.com/health/how-does-endurance-traini...