Big idea that was a stroke of genius for Team GB's rowers

Gold medallist Helen Glover would never have taken up her sport had it not been for an advert seeking tall recruits

The triumphant duo, Helen Glover (left) and Heather Stanning (AP)

Four years ago Helen Glover had never even 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 last 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 respond 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 have long used such schemes to identify talent. But Britain has traditionally relied on amateurs to make their own way through their individual events before coming to the attention of national teams and coaches.

But this time scouts went out looking, knocking on school doors, visiting local sports centres, 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. Her favourite events were cross-country running, tennis, swimming and hockey. But in the end she became an Olympic rower.

"They tested 4,500 of us in groups of 200 at a time," recalled Glover yesterday after celebrating her sensational win with her fellow rower Heather Stanning. "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 the UK at London 2012, often competing in sports that they never even knew they were any good at. It is all part of a wider trend to push back frontiers of athletic achievement through more exhaustive searches of the gene pool.

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 watchful 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 defies the diminutive stereotype of his compatriots at 7ft 2in. 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 even played the sport five years ago. Bobby White, the team's captain, was a semi-professional footballer before he applied and made the switch to handball. Within months of his application being accepted he was training in Denmark under a full-time contract. "No matter what happens for me and the team now, over the last five years I've been on an incredible journey that I never thought I would take," he said the week before the Olympics kicked off.

The hope now is that the talent schemes put in place for London 2012 will continue to pay dividends for the future. 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. "We're getting pretty good at putting these systems in place. If you look around the world, countries are being much more proactive at identifying people who can compete at the highest level. That's what we're doing."

Jonathan Follard, a senior lecturer at Loughborough University, says the evidence suggests the physiques of Olympic athletes are getting more extreme. "There's a real variety of bodies on display, but then humans are very variable."

But being the biggest, the tallest or the lightest is no guarantee of success. "There are so many things that go into a performance," he says. "Not every tall person is going to be a good basketball player, not every heavy person will make a good rugby player. All it can do is contribute."

Others who have found their way into Team GB through the Sporting Giants scheme include Kathryn Fudge and Louise Jukes, who were selected for the women's handball squad. The bronze medallist Vicky Thornley made the rowing whilst Richard Jefferies and Angela Hannah made the canoeing.

Standing tall: Six who excelled

The Sporting Giants scheme, launched by UK Sport in 2007, sought out unusually tall young people who could excel in rowing, volleyball, basketball and handball. Thousands of men over 6ft 3in and women over 5ft 11in were whittled down to form a core of future champions. Team GB's kayak double canoeing competitor, Angela Hannah, won bronze at the 2011 World Cup. Vicky Thornley is part of the women's eight rowing team hoping to win gold. Former rugby player Richard Jefferies was the only member of the British canoeing team selected to race in the canoe rather than kayaks at the Games. Louise Jukes is part of the Team GB handball squad, with Kathryn Fudge. Helen Glover won gold yesterday with Heather Stanning.