A decorated performer at NCAA meets running for Harvard University, Ramsden has stated her desire to qualify for this year’s Games in Paris and took a giant step forward.
She obliterated her own previous personal best of 4:06.51, set at the world indoor championships in Glasgow two months ago.
The 22-year-old was nearly five seconds under her former best outdoor time, set at the Millrose Games in New York in February.
Ramsden was dragged along by a rapid pace in Los Angeles, with the race won by Ethiopian Diribe Welteji in 3:55.25.
She spent much of the race near the tail of the 17-woman group but gradually made up ground.
Meanwhile, veteran shot putter Tom Walsh, who has already qualified for the Olympics, was well below his best at the same meet.
His best distance of 21.02m was only good enough for seventh place, nearly 2m behind American winner and long-time rival Joe Kovacs, who threw a distance of 22.93m.