Salwa Eid Naser of Bahrain reacts after winning the gold medal in the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Jia Yuchen)

Salwa Eid Naser of Bahrain reacts after winning the gold medal in the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Li Ming)

Shaunae Miller-Uibo (1st L) of the Bahamas competes during the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Jia Yuchen)

Salwa Eid Naser of Bahrain reacts after winning the gold medal in the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Jia Yuchen)

Salwa Eid Naser of Bahrain reacts after winning the gold medal in the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Jia Yuchen)

Salwa Eid Naser of Bahrain reacts before the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Li Ming)

Shaunae Miller-Uibo of Bahamas competes during the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Li Ming)

Shericka Jackson of Jamaica poses after the women's 400 meter final at the 2019 IAAF World Athletics Championships in Doha, Qatar, Oct. 3, 2019. (Xinhua/Li Ming)