Athletes such as Adam Gemili, 18, who turned down a soccer contract eight months ago to focus on sprinting and almost made it into the men’s 100 final. Or the dressage medalist who was a groom 18 months ago. Or diver Tom Daley, only 14 in 2008 and still a teen learning how to beat the Chinese.

Money is, of course, the main reason host nations win more. UK Sport has distributed $400 million in the past four years in order to hit medal targets for specific events. After Great Britain won one lowly gold in 1996, National Lottery funding of sports was approved, and athletes, coaches and high-performance scientists benefitted.

Improvement

In 2012, Great Britain has excelled even more than usual in its “sitting-down sports” of cycling, rowing, sailing and equestrian. Gymnasts won four medals, the Brownlee brothers won two in triathlon and Andy Murray was a beam of light for British tennis. On “Super Saturday” last week, Great Britain’s track and field team won three golds — which was two more than it won in Beijing.

UK Sport pumped $37 million into track and field since 2009, $39 million into cycling and $40 million into rowing. Swimming, however, which got $37 million, did not meet its medal target of six. Basketball and archery were big disappointments.

British women won zero gold medals in Atlanta but have 10 so far, with Jessica Ennis, Victoria Pendleton and Beth Tweddle making waves.

Aside from the money spent on, say, the cycling team’s super-secret wheels and battery-powered “hot pants,” home-team advantage derives from the comfort zone of being in a familiar place, following a familiar schedule, eating familiar food. Not having to travel reduces the chance of illness, as well. Athletes are creatures of habit, and in China, they had to do a lot of adapting

Being home gives a tactical advantage. British athletes know every quirk of the velodrome, the way the wind can change in Weymouth, the speed of the track. Their sports labs and physiotherapists are nearby. Oh, and horses are homebodies, too.

Ohuruogu said home cooking might be wonderful, but hometown pressure is not. She did not want to disappoint but lost her 2008 Olympic 400 title to Sanya Richards-Ross.

“It was quite emotional for me to be so close to my home and to feel like these people are like family,” she said. “But it was hard not to let the emotion of wanting to win distract me from my race plan, and I think it did in the end.”

Kayaker Richard Hounslow said he was “gutted” by pressure.

Yet others, such as boxer Nicola Adams and cyclist Bradley Wiggins, said they were buoyed by vociferous support. Distance runner Mo Farah, who grew up in West London and did not perform up to expectations in Beijing, rode the wave of sound around the final lap of the 5,000 and kicked to victory.

What does this augur for Rio de Janeiro, the 2016 summer host? Pelé visited Casa Brazil at Somerset House — where a large countdown clock flashed 1,456 days on Friday — and expressed concern about preparations for World Cup 2014 and the Olympics. And Brazil is not exactly pulling its weight with 12 medals, only two more than Kazakhstan but seven fewer than the Netherlands.

Perhaps India could use an Olympics. The world’s second-most populous country with 1.2 billion people has won only 24 medals since 1900, which gives it the worst per capita record for medals. In London, the United States has won one medal for every 3 million citizens; Great Britain, one for every one million; China, one for every 16 million; Grenada, one for 110,000, and India, one for every 300 million.