Des Moines (US): Olympic champion Dalilah Muhammad shattered one of the longest standing records in women's athletics on Sunday with a superb display to clinch victory in the 400m hurdles at US Championships. The 29-year-old powered home to win in 52.20sec at rain-soaked Drake Stadium, obliterating the 16-year-old previous world record of 52.34sec set by Russia's Yuliya Pechonkina in 2003. "I'm just shocked," Muhammad said.

"My coach kept telling me (the record) was there. I just had to trust that and go for it. "I wanted it so bad I knew I had to go out there and prove myself." Muhammad, the first American woman to win Olympic gold in the event at the 2016 Rio de Janeiro games, later revealed she had an injury scare heading into this week's event, suffering a concussion in a training run two weeks ago. However, she revealed she had been quietly confident that she could threaten Pechonkina's benchmark.