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Dalilah Muhammad of the United States competes during the women's 4X400m relay at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 6, 2019. (Xinhua/Jia Yuchen)

Dalilah Muhammad of the United States competes during the women's 4X400m relay at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 6, 2019. (Xinhua/Jia Yuchen)