Next time you're walking down the street, have a look at how many people are wearing trainers. They're everywhere.

Be it Nike, Adidas, Reebok, Converse or Yeezy, the flat-soled shoes have become a fundamental fashion item for both young and old.

Rare and exclusive designs have even become collectables, worth hefty prices — sometimes in the tens of thousands of dollars.

But how did the sports shoe become such a ubiquitous footwear preference?

Author Thomas Turner has dug deep into its history — which stretches all the way back to the 1800s.

"In Britain, America and Europe in the 19th century, you have the industrial revolution that creates gradually a middle class with time and money to spend on leisure pursuits," he tells RN's Sporty.

Savvy manufacturers, he says, quickly recognised this social change and began inventing new games and pastimes specifically for the middle class.

"Lawn tennis is one of those games," he says.

Early lawn tennis shoes helped prevent players from slipping or damaging the grass. ( Courtesy of Kenneth Ritchie Library, All England Lawn Tennis Club )

Turner says the game was "successfully marketed in the 1870s" and quickly became very popular — first in Britain and then Europe, America "and the rest of the developed world".

"The thing about tennis is that it requires an awful lot of special equipment which makes it very attractive for manufacturers," Turner says.

"One of those things that it requires is a special type of shoe which would allow you to play the game of tennis on a grass court without slipping."

The modern sports shoe, he says, is a descendant of those early tennis shoes.

"I think that's a trend that we see continuing all through the 150 years of the history of the sport shoe where manufacturers embrace new technologies for sports and then gradually they get adapted for everyday use," he says.

But not every incarnation of the tennis shoe is still around today.

The high heel tennis shoe

Turner says the invention of the tennis shoe around 1870 coincided with industrialisation in Britain and Europe.

It came about thanks to the invention of vulcanised rubber — the combination of sulphur and heat with raw rubber created a stable compound which was waterproof and easy to mould.

Sorry, this audio has expired The history of the sports shoe

"Players find it's ideally suited to their needs, as it allows them to run about without falling over and crucially without damaging the grass," Turner explains.

Turner says because tennis was a leisure pursuit for both men and women, the game quickly became about more than exercise.

It was an important date in the social calendar.

"It becomes linked very much to young romance and the idea that men and women can get together and perhaps flirt and play with one another," Turner says.

"Because of this women start complaining about flat shoes, because high heels are becoming fashionable."

Soon, the El Dorado came along to answer that need.

An 1889 advertisement for the high-heeled El Dorado tennis shoe. ( Image courtesy of Kenneth Ritchie Library, All England Lawn Tennis Club )

With the high heel and the lower section of the shoe connected by a flat corrugated rubber sole, Turner says, women could confidently wear the El Dorado without fear of damaging the greens.

The heeled shoe was met with rave reviews.

"Even though it's absolutely ridiculous for playing tennis in, it met the needs of the players in that they wanted to look feminine, they wanted to look attractive and they wanted to look fashionable," Turner says.

Not just a tennis shoe

Soon the sports shoe was being worn beyond the realms of tennis. ( Unsplash: Harry Hundal )

Turner says it wasn't long before the lawn tennis shoe was also being worn off the court.

By the late 19th century, he says, young men in particular were adopting a "sporty look".

"They were just wearing the shoes because they're fashionable and it gives off this athletic masculine and fashion style that people liked at that time," Turner says.

That trend continued through the years, and athletic shoes began to be marketed for different sports.

"You see it being embraced and worn by people playing other sports like running or basketball," Turner says.

"People use it for cycling, people use it for walking."

The market for sneakers grew steadily as people lined up to buy sneakers endorsed by their favourite athletes — like the Converse All Stars promoted by US basketball player Chuck Taylor in the 1920s.

The Converse All Star is a classic example of a sneaker design that sits within fashion and sport. ( Getty: BobGrif )

Turner says a particular pair of shoes can prove formative.

He remembers being a child in the 1990s and desperately wanting to own the Nike Air Max or Nike Air Jordans.

"I spent ages when I was a late teenager wishing I could get trainers that I wanted when I was 11 or 12 that my peers at school had," he says.

"They were really expensive and hardly anyone had them."

But when he could finally afford to purchase them, the line had been discontinued.

Turner believes many current sneaker fans would have a similar story to tell.

"If you talk to anyone who's a sneakerhead or collector they will probably have their own reasons, and if you if you dig deep enough they'll come down to something like that," he says.

Youth, sport and fashion

The sports shoe has since permeated far beyond the want of a teenage boy and into the wider fashion world. But Turner says that took time.

"For a long time the big manufacturers like Adidas, Nike and Puma all found it very difficult to understand fashion and they didn't really know how to deal with it," he says.

Turner says big brands worried if they moved "too far into the fashion market that they would damage their brands in the sports market", and vice versa.

"It's only really through the 1990s and into the 2000s that they realised that there are ways in which they can segment and differentiate their brands," he says.

"They can create a fashion line and a sports line and that these two things can co-exist quite happily."

Turner says sports shoes have helped provide an identity to major brands. ( Getty: Josh Brasted )

Turner, who has authored The Sports Shoe: A History from Field to Fashion, believes an association with youthfulness plays a part in the longevity of the sports shoe.

"Perhaps the popularity of the sport shoe from the late 19th century through to today is connected to the focus that we place as a Western culture ... on youth and how important we think that is," he says.

"Playing high-level sport is the preserve of the young, isn't it?

"So this is something that gives you an air of that. It keeps you vibrant, it keeps you young, so perhaps that's part of the appeal."

Fashion and youthfulness aside, Turner believes that ultimately, the shoes' connection to sport has been crucial in its enduring appeal.

"I think if shoes didn't have the connection to sports the big companies would be in trouble," he says.

Turner says much like in the 1800s, sport allows big brand to experiment with new technologies and make bold design decisions.

"You see this in top sports," he says.

"The most expensive shoes are made using really weird and wonderful materials and odd ways of making them."

The sporting link, he says, also elevates the shoe in the eyes of consumers.

"If you didn't have this connection to sports they'd basically just be making comfy shoes ... which perhaps isn't quite so cool, isn't quite so appealing."