Track and field

The five most exciting clashes to watch

Almost from the moment Usain Bolt finished his 3-for-3-for-3 performance at the Beijing Olympics - three events, three gold medals, three world records - everyone began to wonder what he would do for an encore four years later. That all changed in the span of about 72 hours. Yohan Blake, Bolt's countryman, workout partner and rival, beat the world's fastest man in the 100 and 200-meter finals at Jamaica's Olympic trials. Bolt's subsequent withdrawal from a meet in Monaco only added to the intrigue. [Full analysis; Medal Projections]

Badminton

The sport was invented by the British, but Asian nations have ruled the roost in recent decades as China, Indonesia and South Korea have won 23 out of 24 of the titles offered since badminton joined the Olympics in 1992.

Chinese women, led by world No 1 Wang Yihan, hold all of the top four singles rankings, while the men boast three of the top four. Men's No 1 Lin humiliated long-time rival Lee Chong Wei in the final at Beijing and may only have his Chinese teammates to worry about in London. Women's doubles champion Yu Yang is back, albeit with a different partner in Wang Xiaoli, while long-serving head coach Li Yongbo is still the team's hard-bitten conductor.

Much of this year's intrigue will revolve around which teams can deny China complete hegemony. Women's world No 5 Saina Nehwal appears as equipped as any, and has raised India's hopes of a first badminton medal after upsetting China's best at the Indonesian Open last month. [Full analysis; Medal Projections]

Table Tennis

Since the sport joined the Olympic program in 1988, China has exerted an iron grip - taking 20 of the 24 available golds, including all four at Atlanta 1996 and Sydney 2000. There have been only four non-Chinese golds - three for South Korea and one for Sweden's Jan-Ove Waldner, who won the men's singles in 1992 and remains the only non-Asian gold medalist. But in London, there will be at least two non-Chinese paddlers on the podium, after a new rule limited each country to just two singles entrants.

Underlining China's supremacy, as of June it boasted the world's top five men and top four women. Men's No 1 Zhang Jike enters the singles in London along with Wang Hao, while Ma Long will join for the men's team event. Three-time gold medalist Ma Lin, the reigning singles champion, missed out. Germany's Timo Boll, ranked sixth and part of the team that took silver in Beijing, is the only non-Asian in the men's or women's top 10s.

On the women's side, Chinese world champion Ding Ning topped the rankings in June. Li Xiaoxia will also play singles and Guo Yue is included for the women's team competition. Kasumi Ishikawa of Japan was the highest-ranked non-Chinese, at No 5, with the Singapore duo of Wang Yuegu and Feng Tianwei, part of the women's team that took silver behind China in Beijing, also in the top 10. [Full analysis; Medal Projections]

Weightlifting

Russia has an impressive lineup in the game of power, agility and speed and should challenge the Chinese in the heavy divisions. China, which won one silver and eight gold medals in Beijing, still dominates the lower weight categories. Kazakhstan has a few gold medal contenders like Ilya Ilin, defending Olympic champion in the men's 94kg category, and double world champion Zulfiya Chinshanlo in the women's 53kg class. The quest for gold and the unofficial title of world's strongest woman likely will be a showdown between Zhou Lulu of China and Tatiana Kashirina of Russia.

As always, weightlifting is struggling to contain its dark side - doping. Some would-be medal candidates have been barred from competing in London after failing drug tests, including former Olympic, world and European champion Taylan Nurcan of Turkey, Ukrainian superheavyweight Olha Korobka and China's Olympic champion Liao Hui. [Full analysis; Medal Projections]

Tennis

Roger Federer has set his sights on crowning his remarkable record at Wimbledon by winning Olympic gold on his favorite grass courts. For the second time, and first since 1908, Wimbledon will play host to an Olympic tennis tournament, comprising men's and women's singles, as well as doubles and mixed doubles. Federer isn't the only top star who can't wait for the Games, which start three weeks after Wimbledon concluded. World tops Novak Djokovic and Rafael Nadal also aim at a singles gold at the All- England Club this year. 

In the women's event, French Open champion Maria Sharapova can't wait to represent Russia after missing the 2008 Olympics after shoulder surgery. Newly-crowned Wimbledon champion Serena Williams, world No 1 Victoria Azarenka and China's first Grand Slam winner Li Na are also in pursuit of an Olympic gold for their couintry. [Full analysis; Medal Projections]

Gymnastics

The US women won the world title in 2003, 2007 and 2011 and have produced four of the past six all-round champions, but they have won only one Olympic team title, way back in 1996. They have gone to the past two Olympics as the world champions, only to come up a step short on the podium. This year, the US looks stronger from top to bottom than rivals Russia, Romania and China, the defending Olympic champion.

On the men's side, the Chinese dynasty will face big challenges. China has been on top of men's gymnastics for much of this century, winning five straight world titles as well as the gold medals at the Sydney and Beijing Olympics. But China looked vulnerable in winning the world title last autumn. The Chinese finished qualifying behind Japan and the US, the first time since the Athens Olympics they had finished anywhere but first in any phase of a major competition. The reduction in team size, from six to five, will hurt China most, putting more of an emphasis on all-rounders, something the Chinese lack. The Japanese and the US will pose the biggest obstable. [Full analysis; Medal Projections]

Basketball