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The young fans who bought Ryan Giggs' first book, My Story, when it came out in 1994 got a bit of a shock when they reached page 54.

There, nestling amid images of Giggs celebrating goals for Manchester United, looking moody in Reebok leisurewear and peering out doe-eyed from beneath the curls of his floppy black fringe, was a double-page black-and-white photograph of his feet. And they weren't particularly pleasant.

Giggs' feet stood on a white plinth, his toes curled over its edges. His toenails looked scuffed and jagged-edged, and there was a small, dark bruise on the big toenail of his left foot. Wiry coils of black hair sprouted from the toe knuckles. Giggs' army of female admirers, at whom the book was clearly targeted, would not have expected to find something as unappetising as this between its covers.

A footballer's feet are the tools of his trade, yet we only hear about them—as opposed to what players do with them—when they are damaged, be that David Beckham and Neymar's broken metatarsals, Santiago Canizares' brush with a bottle of aftershave or Darius Vassell's unwise decision to use a power drill to drain a blister beneath one of his toenails.

A cursory look at photographs of football players' feet reveals a litany of calluses, bruises and peculiar bumps and swellings, but for those who play the game at the highest level, ugly feet are the price you pay for a beautiful career.

In Zlatan Ibrahimović's autobiography, I Am Zlatan Ibrahimovic, the former Sweden striker writes about how his friends reacted in horror when they paid their first visit to his new house in Malmo's upmarket Limhamnsvagen district and came across a huge picture of his "two dirty feet" hanging on a wall near the entrance.

"You idiots," Ibrahimovic chided. "Those feet have paid for all of this."

As a podiatrist who has worked with high-profile Premier League clubs for 10 years, Anne-Marie O'Connor has seen more footballers' feet than most people have had hot dinners, and she can testify that they are not always a pretty sight.

Many professional players wear boots that are too small for them to give them better contact with the ball and minimise the movement of their feet inside their boots, which in turn reduces the risk of them turning their ankles. The unwelcome consequences include bunching of the toes, calluses and increased blistering.

The flimsiness of modern boots also heightens the risk of injuries when players' feet are trodden on by their opponents, which can leave them with blood trapped beneath their toenails.

"Players wear their boots one or two sizes too small, and the thinness of the uppers gives them minimal protection," O'Connor tells Bleacher Report. "This leads to calluses, and when they get stamped on by opposing players, they get thick toenails."

A blister may seem relatively innocuous, but if a player reacts to one by offloading weight onto other parts of their foot, they run the risk of developing Achilles problems and even stress fractures.

O'Connor's consulting room at the Fortius Clinic in London's affluent Marylebone area contains a treadmill used to carry out gait analysis on the players in her care. By studying footage of players on the treadmill, she picks up on biomechanical issues that could cause them discomfort or lead to injuries.

She makes casts of the players' feet and sends them to a company in the United States that produces orthotics—thin insoles made of springy, flexible plastic that provide targeted support to injured or problematic areas of the foot. She estimates that 20 per cent of players at Premier League clubs wear orthotics in their boots while playing.

The players at the top of the football food chain—those whose faces adorn the adverts of the major boot manufacturers—benefit from being able to have boots redesigned to their exact specifications. Other players seeking to modify the fit of their boots must either use orthotics or simply make do.

The lightness and flexibility of modern football boots are not conducive to injury prevention. Instead, they are designed to satisfy players' demands for suppleness and speed.

"If you say to a player, 'This boot here will stop you from getting injuries, but this boot here will make you perform better,' they're always going to go for Boot B," says O'Connor.

"The player will choose the boot they find most comfortable and perform best in, be that a super-lightweight boot or one that has preferred traction. My job is to allow them to use that boot but modify it or design an orthotic that makes the boot less injurious or more comfortable."

For the companies that design football boots, input from the players who will wear them provides valuable insight into how the boots need to look and feel. And when the boots hit the market, it is on the feet of those same players that the boot manufacturers will advertise their wares around the world.

"We are in constant conversation with our pro athletes as their feedback and input is the highest form of concept validation. In general, pro players are very curious about new boots since they are the most important tool to do their job," says Philipp Hagel, who is the senior product manager at Adidas Football.

"Elite-level players have a clear idea of what they expect from a boot. Materials, constructions, outsole properties and stud configuration are always points of interest when reviewing and testing new boots and prototypes. Beyond that, the colouration of the boot is very important as boots have become a way to express a player's personality."

Hagel cites Benjamin Mendy as an example of a player who has been closely involved in the design of an Adidas boot. For the FIFA World Cup in Russia, the Manchester City and France left-back was furnished with boots that feature an eye-catching shark design skin. Sadly for Mendy—and Adidas—he has lost his place in the French first XI to the Nike-clad Lucas Hernandez.

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Although he is reluctant to name names, Hagel reveals that some players take a keener interest in the design of their boots than others.

"Some of them go more into detail," he says. "We also have real geeks that like to know everything about every detail and will be very passionate about what we create for them. These players are a great resource for feedback."

Back at her clinic in Marylebone, O'Connor shares some fascinating insights into the biomechanics of the average Premier League football player.

For instance, players who did not wear conventional footwear during their early years—such as those who will have spent most of their time barefoot—develop stronger foot muscles and are therefore less prone to common foot ailments.

"Players who haven't worn shoes until they're older and have played a lot of barefoot football have strong feet," she says. "The muscles at the bottom of their feet are really tough. There are five layers of muscle underneath the foot, but if you wear shoes all the time, you don't use them."

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The way that a player strikes the ball, meanwhile, can have a lasting effect on the shape of their legs, with players who play in wide areas particularly at risk due to the frequency with which they cross the ball.

"Footballers generally have quite bowed legs," O'Connor says. "If you stand on one leg and kick with the other, your weight's always going to be on the outside [of the leg], so over a period of time the bones will evolve into that shape.

"Wingers especially tend to be quite bandy-legged because they do a lot of crossing the ball inwards. If you have straight legs, you can't put spin on the ball because you can't whip round as much, so it's actually advantageous for them to have more bandy legs."

Repeatedly placing all your weight on your standing foot when you kick the ball can even have an impact on the relative lengths of your legs. For normal people whose legs are different lengths, the disparity tends to be no higher than 4 millimetres. For footballers the difference is commonly around 6 millimetres.

Footballers use their feet in training every day—to run, to pass, to shoot, to tackle—but Ruben Jongkind believes that they could be using them better.

Jongkind is a football coach and former triathlete who helped to implement the Cruyff Plan at Ajax following the late Johan Cruyff's return to the club as a technical adviser in 2011.

A central tenet of the plan was specialised, one-on-one work between coaches and promising players. As a former athlete and athletics coach, Jongkind has a deep understanding of biomechanics, and one of the things he works on with players is how to use their feet to get even faster, starting by shortening their stride patterns.

"Foot placement needs to be closer to their body than they're normally used to," he tells Bleacher Report. "Also running on the front part of the foot and landing on the front part of the foot, instead of the heel. Most youth players run on their heels. That's a basic pattern and you have to change that."

Jongkind worked with Christian Eriksen, now of Tottenham Hotspur, during the midfielder's time at Ajax and says the work they did together quickly bore fruit.

"With Eriksen it took only three months to completely change his gait," says Jongkind, who now works for the Cruyff Football consultancy.

"Before he was really not a good runner and he had problems in matches. After these changes, and some extra training, he was second or third in the Champions League list of metres covered in the group phase when he was 18. Now he's a box-to-box player in the Premier League. These detailed changes can make a big difference."

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Jongkind also says it is possible to improve the way a player strikes the ball. He cites Tom Boere, a striker who came through the youth ranks at Ajax and now plays for FC Twente, as an example.

"They're small details, but it's trainable," Jongkind says. "It can be where do you place the standing foot, how you move your arms, which part of your foot hits the ball and which part of the ball you hit.

"[Boere] came in at 16 at Ajax and he was a striker. He was always finishing with the laces. We said, 'Why don't you use the inside of your foot?' And he said, 'I can't.' So we worked on that a lot.

"He got into the second team and scored 15 goals in the first half of the season. He went to Belgium, but then came back to the second league in Holland [with FC Oss] and scored 34 goals in a season. A lot of them were using the inside of his foot."

It is hardly surprising that footballers' feet tend to look a bit unpleasant. From an early age, they wedge them into thin, undersized boots and subject them to a daily barrage of kicks, scrapes and stamps.

Boot manufacturers will accede to their requirements as far as possible, and podiatrists will do what they can to patch them up, but there is only so much that can be done when a footballer's feet must be chisel, hammer, hacksaw and paintbrush all at the same time.

If a player's feet are bruised, gnarled and bent out of shape, so be it. It's what you do with them that counts.