The World Championships are due to take place in Beijing next month and one of the most hotly contested events will be the 100m final.

Usain Bolt is the current title holder, but the Jamaican is expected to face tough competition to hold onto his crown at the Bird's Nest Stadium.

Here, Sports Mole takes a look at the sprinters in the running for one of the biggest prizes in athletics.

Usain Bolt

There can be no doubting that Usain Bolt has been the star attraction in athletics over the past seven years, after becoming a household name for his exploits during the Beijing Games.

A year later at the World Championships in Berlin, he smashed the 100m and 200m world records, and further victories in Daegu and Moscow have seen him become the most successful athlete in the history of the event with 10 medals.

However, the Jamaican has struggled with a number of injury problems and he ran only three races last year, before ending his season early.

He has pulled out of a number of races this season, but he returned to take part in the Anniversary Games in London on Friday and eased to victory with a season best time of 9.87s to silence some of his detractors.

Very few would bet against a fully-fit Bolt retaining his title, but with questions marks hanging over his head, for once he will not be starting as the outright favourite.

Justin Gatlin

With Bolt struggling to reach his best form, the man tipped to claim gold in Beijing next month is America's Justin Gatlin, who won the 100m title in Helsinki 10 years ago, and was runner-up in Moscow.

The 33-year-old's time of 9.74s in Doha in May is the best that any athlete has managed this year and he is currently unbeaten in his last 23 races.

Despite his impressive form, Gatlin is a hugely divisive figure in the world of sport and he has twice served bans for doping.

The IAAF have even said that he will not be considered to win their Athlete of the Year award, but on current form he is the overwhelming favourite to add to his medal collection.

Tyson Gay

Tyson Gay is another former world champion who is expected to be among the medals this year, but he has also been dogged by controversy during his career.

The American was given a one-year ban last May after testing positive for a banned substance, but his suspension was backdated to July 2013.

He has since enjoyed a successful return to the track and clocked a time of 9.87s at the US trials to earn a place at the Championships for the first time since 2009.

However, there are doubts that he can match his 100m best time of 9.69s that he achieved six years ago, and a recent defeat to Gatlin in Monaco did little to suggest that he will emerge victorious in Beijing.

Asafa Powell

Bolt isn't the only Jamaican star who will be in action next month, as his relay teammate Asafa Powell will be hoping to win his first individual 100m gold at the Championships.

The 32-year-old eased to victory at his country's national trials, with former world champion Yohan Blake missing out on a place in the final.

If Powell does end up claiming a medal, then there will be many who will question his achievements, as he has also served a ban for doping.

He tested positive for the drug oxilofrine in 2013 and was handed an 18-month ban in April 2014, but the suspension was reduced to six months following an appeal.

With a season best time of 9.81s, Powell is among the frontrunners for the title, but just like his fellow competitors Gatlin and Gay, he would be an unpopular choice of winner with the fans.

Trayvon Bromell

While many of the more established names are expected to finish in the medal positions, Trayvon Bromell could prove to be one of the surprises of the Championships.

The 20-year-old, who hails from Florida, has made a name for himself over the past year after becoming the first junior to break the 10-second barrier.

He gained further attention during last month's US trials, where he ran 9.84s in the heats, before finishing behind Gay in the final with a time of 9.96s to book his place in Beijing.

The American, who had managed to clock a wind-assisted time of 9.76s in the semi-finals, has already become the 10th fastest man in athletics history and has broken records that the likes of Bolt and Blake hadn't managed at his age.

Beijing may come too soon for Bromell to pick up any medals, but many believe that he has the potential to dominate athletics over the next decade and become one of the sports' leading stars.