Allyson Felix chuan world title 12 a la tling ta a, nu a nih hnua a pakhatna niin, world title lak hnem lamah hian Usain Bolt chu a khum.

Pathianniah khan United States chuan world championship 4x400 metres mixed relay ah gold medal an la a. USA team-a tel, 2005 kuma a gold medal lak hmasak ber tum tawngtu Allyson Felix chuan gold medal a lak belh leh takah chuan world title vawi 12 a la tling ta chiah a ni.

Jamaican sprinter Usain Bolt kha world title la hnem ber a ni thin a, a vanglai khan world title 11 a la hman a, hei hi Allyson Felix chuan a khum ta a. 4x400 metres mixed relay-ah hian Felix bakah Wilbert London, Courtney Okolo leh Michael Cherry te chu US team-ah hian an tel a, minute 3.9,04 second chhungin an thleng a, world record thar an siam zui a, Jamaica leh Bahrain te chuan an tluk pha ta lo a ni.

Pakhatna an nih chiah hian US team te chuan an ram flag an sin a, entu mipui awm mang lohna Khalifa Stadium chhungah an lawm zia lantirna atan lap khat dang tlan belh tawh loin inthlakna lamah an lut zui daih a ni.

Team pariat zinga pasarih te chuan 4x400 mixed relay an tlan dawn hian a hmasa ber leh palinaah chuan mipa an dah a, hmeichhia nen a inchhawkin an tlan a. Poland chuan a hmasa pahnihah mipa an dah a, a hnuhnung pahnihah hmeichhe pahnihte chu an tlantir thung a, a tawpah Poland hi pangana an ni.

Kum 33-a upa Felix hian hmeichhe 200 metres-ah world title vawi 3 a la tawh a, 400 metres-ah vawi 1 la tawhin, hmeichhe 4x100 metres relay-ah vawi 3 a la tawh a, hmeichhe 4x400 metres relay-ah vawi 4 chu a la tawh bawk a ni.