Former world 100-metre record holder, Asafa Powell, knows he will have to watch his back at this weekends National Trials as a number of athletes have been performing well in the event over the last couple of weeks.

"There are a lot of guys out there to put pressure on me and Usain, so I just have to look (out)," Powell said.

"Michael always comes with a surprise at the trials, and Steve Mullings is running well, so I just have to be on double watch," he added.

favoured

Although favoured to easily capture a qualifying spot along with world-record holder Usain Bolt, Powell's below-par performances in his last couple of meets may be cause for concern.

Recovering from an ankle injury sustained at this year's Penn Relays and returning for outings at the Reebok Grand Prix (10.10, 7th) and Prefontaine Classic (10.07, 2nd) in May, produced below-par performances.

However, despite that, Powell said he is not under any pressure, even though he is not 100 per cent fit.

"I am not under any pressure. For the past five years I have been injured at the trials and have still been able to make the team, so I don't see why this year is different."