Ready to roll: Stars to watch out for at the Games

Silence will envelop the Olympic stadium on the evening of August 5 while the world's eight swiftest men crouch in their blocks awaiting the starter's gun.

What happens in the split second after the gun fires and the stadium resounds to the clamour generated by 80,000 spectators will in all likelihood determine the result of the men's 100 metres final.

- London Olympics 2012 - Complete coverage

If Usain Bolt's troublesome right hamstring has healed and he gets a good start there is nobody in the world who can catch the defending champion. If he takes too long to unwind his long legs and body, his Jamaican club mate and world champion Yohan Blake is the probable winner.

The 100 metres is the most unforgiving of all foot races and one mistake by any of the finalists, as Bolt knows from bitter personal experience after false starting at the world championships last year, will mean the race is over.

Unlike the theatre, where Hamlet will always die in the final act, unpredictability and the unexpected give sport its special appeal and there are no guarantees that any of the contestants who line up in Saturday's first round will still be contenders on Sunday night.

The field should also feature American Tyson Gay and another Jamaican Asafa Powell who have both run faster than Blake plus the 2004 champion Justin Gatlin who has returned from a doping ban.

Jamaica is enjoying a remarkable era in both men's and women's sprinting. Jamaicans took five of the six medals at stake in the women's 100 and 200 in Beijing four years ago as well as the 400 metres hurdles title.

Swimming dominates the first week of the Games, athletics the second while gymnastics continues throughout at the North Greenwich Arena.

The Chinese won nine of the 14 gymnastics titles at stake in Beijing and seven out of eight in the men's competition.

Japan's Kohei Uchimura finished second in the all-around competition, after twice falling off the pommel horse, but has since won an unprecedented three successive world titles.

Now 23, Uchimura is known as "Super-mura" and in 2009 and 2011 he finished first in four of the six disciplines.

The swimming features another potentially thrilling individual duel between two athletes from the same country.

Michael Phelps, who won a record eight gold medals in Beijing, will attempt seven events this time before he retires.

In two of them, the 200 and 400 metres individual medley, he will come up against Ryan Lochte, who collected five gold medals at last year's world championships and became the first swimmer to break a long course world record since controversial polyurethane suits were banned.

Lochte has featured in a series of photo shoots in which he displays the Olympic rings tattooed on his right bicep and an alligator on his shoulder.

The flash playboy image is misleading. There is no more dedicated trainer in or out of the water than Lochte, who believes his time has come.

"I have put in the work and it's something that I believe so strongly that I know I can make that happen," he said.

Lochte's 17-year-old teammate Missy Franklin will be in action each day of the competition in an attempt to become the first woman from the United States to win seven gold medals.

Australia hope for a reprise of their golden days by winning their first men's 100 metres freestyle gold since Michael Wendon at the 1968 Mexico City Olympics.

James Magnussen, the overwhelming favourite, holds the world's fastest time of 47.10 seconds and believes he could even break the world record of 46.91 seconds set by Cesar Cielo in the now banned swim suit.

Other rivalries to add spice to the Games include Britain versus Australia in the cycling and the men's triathlon in Hyde Park where Britain's world champion Alistair Brownlee competes against his younger brother Jonathan.

The country which produced Francis Drake and Horatio Nelson now possesses 35-year-old sailor Ben Ainslie, who if he wins in Weymouth will equal the four gold medals of the great Dane Paul Elvstrom.

The Games showcase national strengths in sports which get little international attention outside Olympic years.

South Korea, who have won 16 archery gold medals, more than any other country, will display their skills at Lord's, the spiritual home of world cricket.

Cuba, aided by a system which nurtures talent while banning professionalism, has a proud boxing pedigree, Japan sets the pace in judo and China rules the world in table tennis.

Top individual athletes include Italy's fencer, Valentina Vezzali, a glamorous figure in a glamorous sport, who bids for a fourth individual foil gold medal.

Women's boxing, an exhibition sport at the 1904 St Louis Games, has finally been included in the programme and four times world lightweight champion Katie Taylor has been selected to carry the flag for Ireland at Friday's opening ceremony.

At the age of 30, Russia's Yelena Isinbayeva is battling to prove she can still pole vault higher than any other woman in the world. And Iranian Behdad Salimikordasiabi will show just why weightlifting is such a gripping spectacle when he competes in the super-heavyweight class.