Once a sensible choice of those in middle-age with achy joints, Gen Z have made the functional shoe an ironic fashion status symbol.

Sportswear mega-label Nike's shares have taken £21billion tumble in recent weeks — and insiders say it's because under 25s are flocking to niche footwear brands.

But far from being bad choices, these are podiatrist approved.

Harry Styles led the way last year when he posted a photo to his Instagram story sporting a pair of Hoka trainers, which have ultra-cushioned soles that experts say reduce strain on the joints.

Other brands with 'it' shoes — models that have become widely popular — include New Balance, which correct 'flat feet', arch-supporting Birkenstocks and even Crocs, which were originally design to ease foot pain. 

So what are their health claims and do they really live up to them? MailOnline asks the experts.

Soft landing... with Harry's favourite brand 

Hoka has made a name for itself by designing super-supportive running shoes worn by Gen Z icons Harry Styles, Sofia Richie-Grainge and Kylie Jenner among others.

Launched in 2009, their characteristic chunky, cushioned sole was designed to ease the strain of downhill running on the soles of your feet. 

And its exaggerated, curved shape — known as a 'rocker' sole — alleviates issues from 'heel striking' — the impact of the heel hitting the ground first before the rest of the foot, which can have a negative impact on the joints.  

Marion Yau, a Harley Street nail specialist and podiatrist, told MailOnline: 'Hoka are particularly beneficial for individuals with a heavy heel-strike running or walking gait.

'The extra padding protects against potential injuries by lessening the force transmitted up the leg with each stride.' 

Dr Helen Branthwaite, of the Royal College of Podiatry, said the thick soles might actually make running feel easier, too: 'New foam cushioning materials in high-end running shoe brands [such as Hoka] are performance enhancing, which reduces energy expenditure.  

'They feel springy — and the rocker design of the sole which facilitates walking forward.' 

Former dad-favourite stops feet rolling inward

In a few short years New Balance has gone from dad-favourite to one of the most coveted shoe brands on the planet.  

The firm, which dates back to 1906, now counts actress Millie Bobby Brown, 20, tennis star Coco Gauff, 20, and Kaia Gerber, 22, — daughter of 90s supermodel Cindy Crawford — among its Gen Z fans.

Long endorsed by podiatrists the brand also offers styles with additional support inside that correct overpronation, when the ankle rolls inwards with each stride.

Also known as 'flat feet', this movement causes the foot's natural arch to collapse, creating pressure on the toe joint and potentially increasing the risk of pain, including shin splints, or deformity, such as bunions, in the longer term. 

They also have trainers that tackle supination, when the foot rolls too far outwards. 

Ms Yau said: 'New Balance trainers offer crucial arch and forefoot support. 

'Their spacious toe boxes accommodate bunions and other toe deformities, minimizing pressure and friction that can lead to corns.

'And supportive foam midsoles absorb shock, reducing the impact on feet and legs and potentially lowering the risk of shin splints.'

Asics  

In a nine-second TikTok video from Gen Z influencer @vivienarchive, she tells her 465,000 followers: 'Sneakers that went from cringe to cool pt.6.' 

The clip, seen over half a million times, then cuts to a montage of the JJJJound x Asics Gel-Kayano 14 trainers.

They've also been spotted on the likes of Hailey Bieber, 27, and Kaia Gerber.

Runners have long sworn by the brand’s Gel cushioning system, which is designed to absorb shock and provide a smooth ride. 

Asics trainers also tend to have a wider toe box, designed to provide more support for overpronators or those who want a little extra room to move their toes around. 

Its Gel Kayano offers a wider base, through the heel, midfoot and forefoot, which experts have said helps to stabilise the foot.

The heel is also rounder to better control impact.

Dr Branthwaite told MailOnline: 'Fashion trends have been moving towards specialised athletic footwear for everyday use. 

'This footwear type is designed to endure impact, enhance performance and be supportive for your feet so can offer many benefits, especially to those with foot pain.'

Birkenstocks 

But Gen-Z's fascination with orthopedic-looking shoes is not limited to trainers. 

After Margot Robbie sported a pair of pink Birkenstock Arizona sandals in the Barbie movie last year, searches for the German shoemaker surged. 

Endorsed by podiatrists for decades, the insole of the brand's sandals and clogs offer arch support that runs along the sides of both foot beds for greater stability. 

The heel cup in Birkenstocks is also heralded for giving stability helping prevent overpronation.

Dr Branthwaite said: 'Look at the angle of the sole in the arch. 

'A shoe that is very flat with no difference between the heel and the front of the shoe can be useful to strong feet or flat feet.

'Your foot is a complex jigsaw puzzle with 26 bones, 33 joints and over 100 muscles, ligaments and tendons. 

'You want your footwear to help your foot needs, not worsen them.'

Crocs 

Love them or hate them, Crocs — the rubber clogs that launched in 2002 — are here to stay, having sold more than 300 million pairs across 90 countries. 

Originally produced in Canada intended as footwear for boating, they were designed specifically to eliminate plantar pain — the part of your foot connecting your heel bone to your toes — by supporting the arch and cushioning the heels. 

The room they offer for the toe also affords the front part of the foot room, especially for people with bone deformities like bunions and hammer toe. 

The brand has taken to Instagram and TikTok and partnered with influencers and celebrities to attract a Gen-Z audience.

Actress Millie Bobby Brown and American TikToker Charli D'Amelio are among its fans.

The 20-year-old 'Stranger Things' star even took to Instagram lauding the brand's limited edition collaboration with Justin Bieber saying she was 'in love'. 

Ms Yau told MailOnline: 'These shoes are perfect for the summer due to their incredibly lightweight and easy-to-wear design.

'The ventilation ports and breathable construction effectively reduce moisture buildup, preventing unpleasant odors and keeping your feet dry and refreshed.'

Experts, however cautioned against wearing Crocs over long periods given their cushioned wide fit design. 

Dr Branthwaite said: 'Although a soft cushioned shoe may be immediately comfortable to put on over a longer period of wearing, the function and mechanics of moving in that shoe can cause discomfort, fatigue and pain. 

'Think walking in soft sand or a trampoline, it feels good for a while but after a long-distance it causes fatigue and aching muscles.'

She added: 'If the shoe can be bent in half or wrung out like a dish cloth it will make your foot work harder as the muscles will need to be more active to keep the shoe on and support normal function. 

'When you already have issues in your foot this can cause you pain or make existing problems worse.'