American teenager Missy Franklin captured her fourth gold medal at the LondonOlympics on Saturday when the United States broke the world record to win the women's medley relay final.

Franklin, swimming the backstroke leg, teamed up with breaststroker Rebecca Soni, butterflyer Dana Vollmerand freestyler Allison Schmitt to win the gold in a combined time of three minutes, 52.05 seconds.

The Americans led at every handover and shaved 0.14 seconds off the previous world record of 3:52.19 set byChina at the 2009 world championships in Rome when the now-banned polyurethane bodysuits were still allowed.

Australia finished second to grab the silver medal while Japan came third to collect the bronze but neither were able to keep up with the Americans after Franklin gave them the lead after the lead-off leg.

Franklin, 17, also won gold in the 4x200 freestyle relay and the 100 and 200 backstroke and became the first swimmer in London to win four golds.

Vollmer and Schmitt both won their third gold medals in London while Soni picked up her second.