Olympic and world sprint champion Usain Bolt should seriously consider running the 400 metres, Michael Johnson said on Monday.
Johnson, the former 200 and current 400 world record holder, arrived in Kingston on Monday to attend Bolt's charity event on Dec. 5.
He told reporters the 400 would give Jamaican Bolt a new challenge.
"He will have to find a new challenge and I think the 400 metres will be a new challenge for him in a couple of years," Johnson said.
"There is no one that can beat him (in the sprints) at this point, so where does the motivation come from?"
Bolt broke Johnson's 200 record at the 2008 Olympic Games in Beijing clocking 19.30 and lowered the mark further in Berlin earlier this year with a 19.19 run. He also holds the 100 world record at 9.58.