Game, set and match ... a history of sport and fashion

But what the athletes wear, the colours, fabrics and styles, will have a direct influence on fashion. The trainers they endorse will sell out and the polo shirts they wear will become high-street favourites. Even their accessories (bags, sweatbands and socks) will be scrutinised, dissected and then reconstructed for the catwalks.

Designer Stella McCartney unveiled the Team GB kit on Thursday to mixed reactions. Among the criticisms was her decision to deconstruct the Union Flag to leave a mostly dark blue, turquoise and white design with less emphasis on the red, which is mainly found in the shoes, socks and neckline detail.

At the launch athletes including heptathlete Jessica Ennis, gymnast Louis Smith and BMX cyclist Shanaze Reade waxed lyrical about it. Not everyone was convinced. Six-times Olympic medallist cyclist Bradley Wiggins tweeted: "Oh dear, the Olympic kit!!".

Hurdler Andy Turner reported on Twitter that his fans had deemed it to "look like a posh Scottish flag".

There will also be a Team GB retail offering which McCartney, who has her own sports label with Adidas, has worked on.

Sport and fashion weren't always so closely linked. If you think back just 50 years the two worlds appeared to have very little to do with each other. Sportswear was for athletes or average people indulging in a bit of exercise, while fashion was about catwalks and aesthetics. The same person might have worn both styles of clothing (one for a spot of golf or perhaps a bit of fishing, and fashion apparel for everyday life) but never at the same time.

Of course appearances can be deceiving: a square-cut woollen ladies' jacket may have its origins in sportswear; a pair of leather men's shoes could have been inspired by football boots; a logo T-shirt would find its fabric ancestors not in the ateliers of Paris but in a sporting ground.

What hangs in our wardrobes has as much to do with athletes and sport as it does with designers and trend forecasts.

Ligaya Salazar, who edited the 2008 book Fashion v Sport, describes the relationship between the two fields as "intrinsic". Salazar, the curator of contemporary programmes at the V&A Museum in London, says: "Sportswear became so much part of everyday life that it was only a matter of time before the two would come together. I think sportswear brands recognised that fashion designers' influences were from sportswear and streetwear, and they realised their items were being used as fashionable clothes."

In Salazar's opinion the touch-paper of fashion and sport's modern relationship was lit in the 1980s. It was then, she says, that sportswear was adopted by people for their everyday wardrobes. Street style, at first in America and then around the world, was influenced by sporting apparel – men wore baseball caps and boxing-inspired boots, while shellsuits (previously used only by athletes for keeping warm) became popular on the high street. No-one would argue that it was high fashion, but these were the clothes young people were wearing.

These street styles began to influence the catwalk. "The relationship is due to the fact that people adopted sportswear as a fashionable statement in the 1980s," suggests Salazar. "I think the eighties were an important point for fashion and sportswear because it was a time when they could fit together. Then it was normal that someone would do an entire collection in jersey or one based on tracksuit bottoms."

The 1980s may have been the birthplace of modern sports fashion, but it's not where the journey started. We need to travel back to the start of the 20th century when one Gabrielle Coco Chanel was blazing a trail. It's no secret that Chanel helped to liberate women's bodies from 19th-century corsets with her loose-fitting dresses and jackets, but it's less well known that those early garments were inspired by the leisure and sportswear of the day.

As the quest for the body beautiful continued, this stylistic marriage strengthened. As the strong, athletic body was held up as the epitome of perfection (as opposed to those waifish flappers of the 1920s) designers looked to dress that body in the most flattering way – and what better to flatter the toned muscular physique than with apparel inspired by sport?

Trends moved too, from Christian Dior's hourglass New Look to figure-fitting garments described as "body-con". Sporty fabrics such as lycra and jersey made an impact in the 1970s disco era, before designer Azzedine Alaia furthered the trend with his seductive figure-clinging look.

In the 1990s and 2000s sport continued to infiltrate everyday clothing in the form of stylised trainers, sweatshirts and, in menswear particularly, a proliferation of sportswear as casualwear. Today's look is constantly linked with sport. Polo shirts, trainers, jeans, shorts, tracksuits, jersey dresses and lycra creations can all be traced back to innovations in sport. Even the humble tweed jacket has its roots in country sports, not formal wear. "What is interesting about the symbiotic relationship between fashion and sportswear is that it is by no means informal," explains Salazar, who holds up tailored tweed garments as an example of this.

It is perhaps a little ironic that many of the clothes that Salazar says are "informed by sportswear" are worn for relaxation. Tracksuit bottoms are often favoured by women and men for slouching on the couch, eating crisps and watching The Apprentice, while T-shirts are worn on evenings out. It would appear the heritage of these garments is somewhat lost.

So what is the relationship today? Is it merely a marketing manager's dream – David Beckham posing in his smalls for H&M billboard adverts – or does the design relationship mean more than that?

"What I'm interested in is more than getting David Beckham and putting him in a pair of pants," says Robert McCaffrey, brand director of Italian label Dirk Bikkembergs. Bikkembergs, one of the Antwerp Six designers who rose to fame in the 1980s, has always had a strong sporty figure as his muse. "It's easy to say now 'sport and fashion are intertwined', but back then [in the 1990s] it was really rather controversial, what we were trying to do."

McCaffrey believes the trend was boosted when designers such as Yohji Yamamoto and Stella McCartney paired up with sports brands to create diffusion labels. Certainly, McCartney's and Yamamoto's ranges for Adidas are among the most successful collaborations between designer and high street. McCartney's Adidas collection is regularly a favourite at London Fashion Week and is stocked on designer websites such as Net-a-porter.

Appearances, though, are only one part of it. Fabric development and technology is also key. "I don't think fashion can claim to be at the cutting edge of fabric technology as other people with massive resources like Nike can be," argues McCaffrey. "But what I think is interesting is the step down from that, a year later when Nike has abandoned that fantastic material and they've gone for one which is half a gram lighter, then that last material becomes public and then that's when it's interesting because designers cut it and use it slightly differently."

It does appear fashion gets sport's cast-offs. Salazar says: "Sportswear companies have the most funds to research textiles. It will always inform fashion because those textiles will filter into what designers want to experiment with."

Perhaps the most obvious impact sport has had is to make us all dress a little less formally. The stiff shirts for men and the day dresses for women of the 1940s and 1950s have been largely replaced with casualwear. This lack of day-to-day formal attire is often criticised – we have turned into a nation of slobs, say critics.

Is that fair? "We just have more freedom," argues Salazar. "People lament the fact that we don't dress up in certain ways any more but we can – it's not something that has been prevented by the influence of sport on fashion. We just have more variety now, more freedom. When you look at people's lifestyles, being as busy as they are, I think the functionality that sportswear intrinsically has will come towards the forefront. Sportswear in fashion is here to stay."

Jen McIntosh, rifle shooter