China's Zhou Hongzhuan broke the world record to win the women's 400m T53 title at the 2016 Rio Paralympics.The 27-year-old clocked 54.43 seconds to eclipse the previous record of 54.69 set by Australia's Angela Ballard in June, reports Xinhua on Sunday.Speaking about the feat, Zhou said: "I am very happy and excited to win this medal because I trained a lot but I did not expect to win."It was Zhou's fourth Paralympic gold medal. In addition to Sunday's triumph, Zhou won the 400m T53 and 800m T53 in London four years ago, and the 800m T53 at the Beijing 2008 Games.She also took silver in the women's 100m T53 on Thursday. Zhou's leg impairment is the result of polio.