Anyone who has a parent or grandparent in their 90s will know how for many people of that age simply walking from one room to another can be a gruelling test of endurance.

As cruel as old age can be, it is at least a distant concern for most of us. We can console ourselves that we have plenty of time to fulfil all those dreams that require being fit and active.

But for a tiny proportion of children who suffer from a rare form of juvenile arthritis time is something that simply isn't on their side.

Amelie Shaikh is one of around 12,000 kids in the UK with the debilitating condition.

For the 13-year-old, who lives in Kensington, any kind of physical activity puts a huge strain on her body.

Amelie Shaikh with her mum Caroline and TV presenter Paul O'Grady who she met in hospital this summer

So when she takes part in a 5km run this weekend it will be an incredible undertaking.

Her mum Caroline, 41, explained: "She's essentially like a teenager trapped in a 90-year-old's body so doing a 5k is like doing a marathon at a sprint for her.

"She'll be using a scooter because I do not want her to be in any pain and I want to make sure she enjoys the day.

'It's difficult to get through the school day'

"She needs a scooter and special shoes to get around and there's a lot of metal inside her. She struggles, she can basically walk as far as your great gran could.

"When she's not at school, nine times out of 10 she's at hospital or completely worn out so she's not really been able to have hobbies. It can be difficult to even get through the school day because her feet really hurt.

"That said, she did physiotherapy twice a day every day at the hospital so she's pretty strong. She's definitely not fragile, she's got good glutes."

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Amelie being discharged after years of hospital care allowed her to return to Francis Holland School in Regent’s Park on September 5.

Caroline said: "She absolutely loves school. She's an only child so her friends at school are everything to her and it's been so nice for her to go back.

"Her favourite subject is science. She wants to make robotic prosthetics when she grows up, which is not what I would have ever dreamed of for her.

"I think she realises that there are so many people out there struggling without walking aids they need and it could be great for her to create these things. She's fascinated by people's gaits and that's why if she can help someone like her she will be very pleased."

Amelie has been treated at Great Ormond Street Hospital since she was a baby (Photo - John Stillwell/PA)

The 5km run Amelie is doing this Saturday (October 13) will raise money for Great Ormond Street Hospital , which has treated her since the age of one and a half.

She is taking part in the Race for Kids in Hyde Park and has so far raised more than £1,000 in donations.

Before being discharged from Great Ormond Street, in August, she featured in an episode of Paul O'Grady's Little Heroes on ITV 1 filmed at the hospital during the summer, which showed her undergoing surgery on her ankle to help her walk.

Race for Kids is an annual event to raise funds for seriously ill children at Great Ormond Street.

So many friends still in hospital

Amelia will be running the race accompanied by her mother and their Maltese terrier, Buster.

Caroline added: "She's running because she wants to prove something to herself and to everyone who's donated. She also realises she is one of the lucky ones, since she left a lot of friends still at Great Ormond Street, so she wants to do it for them.

"We've got amazing friends at the hospital, it's like a family there. There's so many kids with arthritis from all walks of life, all ages and all levels of disability and they mean a lot to her."

Great Ormond Street head of community fundraising Laura Savory said: "We’re thrilled that Amelie got to ring the end of treatment bell recently to mark the end of her treatment at the hospital and that she and her family are taking part in the run this year.

"All the money raised from the event will help us make a real difference to seriously ill children and their families from across the UK. I would encourage everyone to join us on Saturday and to either jog, walk or wheel their way around the course and enjoy the fantastic family festival after the race."

To register to take part in the Race for the Kids, click here .