The big idea that was a stroke of genius for the golden girl of GB rowing

August 1, 2012: Helen Glover and Heather Stanning celebrate winning GB's first gold of the games (GETTY IMAGES)

Four years ago Helen Glover had never stepped foot in a rowing boat. Yesterday she stood by the waterside in Eton Dorney clutching one of Britain's first two gold medals. The past half a decade has been a roller-coaster ride of sheer determination and grit. But none of it would have been possible had the Truro-based teacher not taken the spontaneous decision to reply to an advert seeking unusually tall and fit people to become potential Olympic athletes.

When Britain won the Olympic bid it launched a talent-spotting scheme to look for potential gold-medal winners. Plenty of other countries use such schemes to identify talent but Britain has traditionally relied on amateurs to make their own way.

This time scouts went out looking, knocking on school doors, visiting sports centres, and chatting up coaches to see if they could find the next generation of medal winners. UK Sport also put out adverts, in 2007, calling on people to sign up to their so-called "Sporting Giants" scheme – what we needed, it seemed, were tall people who could compete in rowing, volleyball and handball.

Glover was already sporty but in the end she became a rower. "They tested 4,500 of us in groups of 200 at a time," she recalled yesterday. "I remember sitting in a room in Bisham Abbey [Manor] and someone saying: 'A gold medallist in 2012 could be sat in this room. Look around you.' I thought: 'Right, I'm going to make that me.' It was quite surreal."

There are now 10 "sporting giants" representing Great Britain at London 2012, often competing in sports they never knew they were any good at.

As talent-spotting schemes have evolved, so has the variety of body types on show at the Games. Unusually tall people are pushed towards basketball, volleyball and handball; scouts keep an eye out for any child with large hands and a knack for swimming, while light-framed boys and girls are honed from an early age in gymnastics.

This summer's Games are no exception. Whether it's the freakishly swollen thighs of road cyclists, to the shoulder wings on swimmers or the eye-watering bulk of weightlifters, an entire gamut of physiques is on display. The tallest athlete competing is Zhang Zhaoxu, a Chinese basketball player who, at 7ft 3in tall, defies the diminutive stereotype of his compatriots. At the opposite end of the spectrum is the pint-sized Japanese gymnast Asuka Teramoto, a 4ft 5in bundle of acrobatic prowess who weighs in at 30kg.

But spare a thought for the judo players who have to go up against Ricardo Blas Jr, known among his fans in Guam as "the Little Mountain". When he first made an appearance, at Beijing, on a wild card, he smashed all the records for being the heaviest athlete in the history of the Olympics at 210kg. In the intervening four years he has put on another 8kg bringing him to 218 kg (34 stone). But sheer size isn't always a boon – even in the heavyweight judo division. At Beijing, Blas Jnr lost all his fights.

For Britain, however, there is no doubt that our quest for tall, athletic people has paid dividends. Britain's handball team now contains four players who had never played the sport five years ago.

The hope now is that the talent schemes put in place for London 2012 will continue to pay dividends. A similar scheme to get more women into sport – Girls4Gold – was launched two years ago with the intention of targeting Rio 2016.

"It's not just about London," said Chelsea Warr, head of athlete development at UK Sport.