Can lightning strike twice?
Usain Bolt will answer that question when he takes to the track to defend his gold medals in the 100- and 200-meter dashes from the 2008 Olympic Games in Beijing. The Jamaican sprinter broke the world record in both events in Beijing.
The 2012 Olympic Games in London will pose new challenges and challengers for Bolt. No longer is he the new, up-and-coming star in track and field trying to keep up with the likes of Tyson Gay and Asafa Powell. Now, he is the superstar that every other sprinter wants to beat.
Jamaican track team doctor Winston Dawes says Bolt is 100 percent healthy and will be in perfect shape to defend his titles.
He will have to be, with these five men wanting to unseat him in London.
Asafa Powell will try to take back the reins as the top sprinter from Jamaica in the 2012 Olympic Games in London. He had one of the best views in the house in Beijing in 2008 when Usain Bolt soared to win his two individual gold medals.
Powell is a long shot to win gold in the 100, as he placed third in the Jamaican trials behind Bolt and Yohan Blake. Although, you never know if Bolt is truly healthy, and a bad start from any of the other sprinters could provide just enough window for Powell to return to the top of the medal stand.
Justin Gatlin is continuing to work on his redemption story at the 2012 Olympic Games. After winning gold in 2004 at the Olympic Games in Athens, he was hit with a doping suspension from 2006-2010.
He won the 100 meters at the U.S. Olympic Trials by finishing ahead of Tyson Gay with a time of 9.8 seconds. He will likely have to put together an even faster race if he plans on winning gold in London.
There are some people that would say that Gatlin doesn't belong in London due to his past transgressions. Others would argue that he has paid for his actions and should be allowed to compete. Whether you like him or hate him, you can't deny that there is a very short list of sprinters that can beat him.
Wallace Spearmon Jr. will give Usain Bolt a challenge in the 200 meters in London. Coming back from the devastation of being disqualified in 2008 Beijing Games for stepping out of his lane, expect him to be very focused.
Spearmon ran the 200 meters in 19.82 seconds during the U.S. Olympic Trials. He owns two of the five fastest times in the world this year.
He is the primary American hoping to take on the Jamaican duo of Bolt and Yohan Blake in the 200. Hopefully for Spearmon, whatever he runs this time will count.
Tyson Gay is the American to watch in the 100 meters at the 2012 Olympic Games. Although he finished second to Justin Gatlin at the Olympic Trials, he is still the world's second-fastest man with a 9.68-second finish on his resume.
2008 was supposed to be Gay's moment in the spotlight until Usain Bolt flashed on the scene. Unfortunately, due to injury in the trials and a dropped baton, he never made it to a single finals that year.
In what could be the 29-year-old's final Olympic Games, he is still in search of his first medal. It's hard to believe that such a world class sprinter has yet to earn the ultimate decoration for such an athlete. That could be the added motivation that gets his worn-and-torn body across the finish line first in London.
Yohan Blake is the most likely challenger to ruin Usain Bolt's chance of defending his 100- and 200-meter gold medals.
Blake set the best time of the year in the 100 meters during the Jamaican Olympic Trials. His 9.75-second finish shocked the world, as he finished 0.11 seconds ahead of Bolt. He finished ahead of Bolt in the 200 meters at the trials as well.
Blake is Bolt's training partner and should make for an interesting finals to see if yet another Jamaican sprinter can defeat his teammate and take over the reins as the world's fastest man.
Jamal Wilburg is a Featured Columnist for Bleacher Report.