Michael Johnson believes if Usain Bolt is able to pull off an unprecedented 'triple triple' at the Rio Olympic Games the Jamaican sprinter's exploits would be the greatest sporting achievement of all time.

Bolt won 100 metres, 200m and 4x100m gold medals in each of the last two Games and arrived in Brazil aiming to make history in what the 29-year-old stated will be his last Olympics.

Four-time Olympic champion Johnson does not believe there would be a sporting feat to match Bolt's achievement if the sprint king can pull off yet another treble.

Speaking courtesy of Michael Johnson Young Leaders, the legendary American told Omnisport: "It is extraordinarily significant if he can pull this off because no athlete has ever done this.

"He's the first athlete ever to repeat his 100, 200 and 4x100m Olympic gold medals, having done it in 2008 and then repeating it again in 2012. To do that again in 2016, three different times, is incredible. It's on par with nothing.

"I can't think of anything that you could compare that to. It is a real representation of consistency and longevity at its best in an area that's probably the most difficult in all of sport.

"To be that consistent and repeat, sprints every four years, on the day, at the moment, you've got to deliver your best performance. That's pretty difficult if you compare that to other sports whether it be golf or tennis with grand slam events, you have those events every year.

"You have an opportunity every year to do it again. This is every four years, on the day, at the moment you've got to deliver the performance.

"You may be great the week before, you may be great the week after but a slight injury or a bit of food poisoning like I experienced in 1992 as an Olympic champion favourite for 200m. I was ranked number one in the world all year long, undefeated but not ready to go on that day.

"That sort of puts it into context just how significant this would be if he would pull it off."

Bolt pulled out of the Jamaican Olympic trials after suffering a hamstring injury last month, but won on his return in the Diamond League meeting in London and Johnson expects him to be firing on all cylinders in Brazil.

Johnson added: ""He ran very well in London so I think that there's really no more question marks regarding his fitness in terms of health.

"The ideal scenario would be him getting in more races prior to the games which he's not going to have the opportunity to do, but as we've seen in the past he has shown that he doesn't need races to prepare.

"He can use the rounds, preliminaries and quarter-finals and elimination rounds to get to the final as tune-up races. Based on the time he ran in London, I don't think that anyone would argue that he's ready to go and in good position to defend his titles."