Is nature or nurture behind Jamaica's need for speed?

Some say it’s in the genes. Others credit the local yams and green bananas. Sports analysts reckon world-class coaches played the key role. Cultural commentators credit a straightforward love of speed which, in previous eras, inspired the nation’s most gifted sportsmen to devote their careers to sending cricket balls towards rib cages at high velocity.

The utter domination of sprinting by a small Caribbean island with a population of less than three million has left commentators reaching for superlatives. Of the 12 individual medals so far awarded in London’s 100 and 200 metre events, eight have gone to Jamaicans. Three were gold. In 2008, they won all four of the men’s and women’s races.

Usain Bolt will tonight attempt to increase the haul by leading his country’s men to a second successive victory in the 4x100m relay. The women went late last night. Whatever the results, Jamaica now represents as unrivalled a force in sprint running as Kenya at the middle and longer distances. But why?

One obvious answer is genetic. Average Jamaicans are blessed with long limbs, low fat levels, and narrow hips. Previous Olympic champions such as Donovan Bailey, who won Gold for Canada in 1996, and Britain’s Linford Christie, showcased the natural potential of the build: they were born in the country, before emigrating as children.

So much for “nature.” On the “nurture” front, Jamaica’s relatively healthy staple foods play a role. Most star athletes come from rural areas, where they grow up walking long distances and drinking water instead of soft drinks, and eating lots of vegetables. When Bolt won gold in Beijing in 2008, his father, Wellesley, told reporters that his speed stemmed from yams that grow in his native north-west of the island.

Coaching has almost certainly also been pivotal. In previous eras, Jamaica's top young athletes often emigrated to top US colleges. Often they never returned. Now the world’s best coaches, including the great Dennis Johnson, and Bolt's mentor Glen Mills, are based at home. So they tend to stay.

The final piece of the jigsaw is cultural. Sprinting is now Jamaica’s de facto national sport. Children start at the age of three, and begin competing at six. They generally train on grass, which many believe is more effective than artificial surfaces for developing athletes. The national school track championships, known locally as “Champs,” are now more closely watched that West Indies test matches and national football fixtures.

Of course, to the heroes of any fashionable sport come spoils. For ambitious young Jamaicans, sprinting has duly come to represent a path out of poverty. Bolt earned an estimated $20m last year, according to Forbes. He drives fast cars, dates beautiful women, and was this week described by Reuters as: “the island’s top celebrity after... Bob Marley.” In the land of reggae, you don't get any bigger than that.