Su Bingtian (R) sprints with Christian Coleman (C) of the United States during the men's 60 meters final of the IAAF World Indoor Championships at Arena Birmingham in Birmingham, Britain, on March 3, 2018. Su blazed to an Asian record of 6.42 seconds to take the silver medal. (Xinhua/Tim Ireland)

China's top sprinter Su Bingtian has the ability to improve on his personal best - 9.91 seconds, says American coach Randall Huntington.

SHENYANG, China, Aug. 3 (Xinhua) -- China's top sprinter Su Bingtian has the ability to run faster than his personal best of 9.91 seconds, said his coach Randall Huntington here during the national trials on Saturday.

The 29-year-old Su twice ran 9.91s in June last year to equal the Asian record, setting another milestone of his career after he became the first Chinese to break the 10s barrier in Eugene four years ago.

Huntington, former coach of long jump world record holder Mike Powell, believed his protege can run even faster.

"His ability decides that he can faster than 9.91. Will he run faster than 9.91? I'm not going to predict whether he will or won't, because it's all going to depend on what he does in that particular race. Right now the elements are coming together for him to run faster. But it's gonna take more races," said Huntington who joined Su's coaching team in late 2017.

Su Bingtian celebrates after the men's 100m final of athletics at the Asian Games 2018 in Jakarta, Indonesia. Su claimed the gold medal with a game-record 9.92 seconds. (Xinhua/Pan Yulong)

Su, who already secured his berth at the upcoming IAAF World Championships in Doha before the two-day national trials here, clocked 10.19 seconds and finished second in Friday night's 100m final. It was his first race since he was sidelined with a back injury in May.

Huntington said Su recovered well in the past two and a half months but it takes time for Su to readjust to competition.

"While we were training in Switzerland, we went to Roger Federer's doctor and he is a back specialist. And that specialist did an incredible job," said the American.

"This is a test event because we've been working on many technical aspects of his 100 meters. This is his first opportunity to actually get out and try some of those things," he said.

Su will turn 30 this month, an age at which he will be called a veteran and normally is considered reaching the end of one's athletic career in China but Huntington believes Su still "has plenty of gas in the tank".

"He's not that old. He'll be 30 at the end of the month. Look at Gatlin, look at Carl Lewis. These guys raced until their late thirties," he said.

Justin Gatlin stunned Jamaican legend Usain Bolt in the 100m final to lift the 2017 world championships title when the American was 35 while Lewis retired at 36 with nine Olympic gold medals and eight world titles.

"He has plenty of gas in the tank to get him to Tokyo. And I'm not killing him in training. So his body is not getting beat up. So that's preparing it to Tokyo," said Huntington.