The 18-year-old from Centennial, Colo., eclipsed the mark of five set by American Tracy Caulkins in 1978 and Australian Libby Trickett in 2007.
Franklin, who won four golds and a bronze at the 2012 London Games, joins American men
Franklin swam the opening backstroke leg for the U.S., which included
"I'm not really sure where that came from but I'm really happy with that," Franklin said po her record-setting performance. "I knew I had to get out there for my team.
"We had really tough competition in that race, so we were sitting there in the ready room and we said, 'No matter what happens, we're just going to do our best and have fun and we can't let each other down if we do that.' So I just went out there and it hurt really, really bad, but now we're done and we're all super excited."