US freestyle great Katie Ledecky posted the second-fastest 400m free time of her storied career on Thursday, clocking 3min 56.81sec to run down Summer McIntosh for a second stunning victory in as many days at the TYR Pro Swim Series meeting in Florida.
Ledecky, who posted the second-fastest 1,500m free time in history on Wednesday, overshadowed the return to action of Paris Olympic star Leon Marchand, who posted a personal best in finishing third in the men's 400m free in his first competition in four months.
With the World Championships in Singapore coming up July 27-August 3, nine-time Olympic gold medallist Ledecky produced the fastest women's 400m ever in a US pool -- and her fastest since she set the American record of 3:56.