Image copyright Uni Bristol Image caption New mobility tech: (L) A stiffening "cuff" to support the knee; (R) artificial muscles (background) can raise a robotic leg

Johnathan Rossiter proudly displays his new trousers. Brightly coloured and fit for the running track, but packing more than just Lycra. They'll be robotic.

"We are all going to get older and our mobility is going to reduce," he says. "What we want to do is give people that extra bit of boost, to maintain their independence as long as possible."

A team of British researchers thinks the future lies in wearable soft robotics. They've developed robotic muscles; air-filled bubbles of plastic that can raise a leg from a seated to a standing position.

Getting this technology into the trousers might be 10 years away, but it is set to give that added boost to our ability to stand and walk when we need it most.

Who wears the trousers?

Prof Rossiter, from the University of Bristol, explained that "there are about 10 million people in the UK with disabilities". This includes people with functional disability, but also those with mobility problems in old age.

By 2046, the proportion of people aged 65 and over could grow to nearly a quarter of the population. About 1.2 milllion people in the UK have had a stroke.

Many of these people will need mobility assistance. The problems experienced by people may be in walking, sitting and standing, but also with other day-to-day tasks like dressing.

Social services will be under increasing pressure to provide more carers and occupational therapy. This stimulated work by Prof Rossiter to use £2m of EPSRC funding to come up with robotic solutions that would improve on the conventional aids of walking stick/frames, wheel chairs, or mobility scooters.

Researchers were showcasing the technology and some of the clothing developed for the first time at this week's British Science Festival in Hull. Prof Rossiter told the BBC: "One of our goals is to replicate human muscle in an artificial form, so that you can sew them into your trousers and you've got your power trousers."

What technology is involved?

Prof Rossiter has teamed up with scientists from across the UK to bring together nanoparticle science, functional 3-D printing, smart material development and artificial muscle technology.

"Soft robotics can make materials and structures that behave in a really sophisticated way in contrast to conventional robotics" said Prof Rossiter.

"We have evolved organisms that are so sophisticated in their movement in their sensing and in control, like the octopus, they can bend and twist can squeeze into small spaces. We can take some of these capabilities and put them into artificial muscles, put them onto clothing."

At the science festival, Prof Rossiter's team demonstrated the artificial muscles. To my eye, they look like strings of cocktail sausages made from clear plastic (that feels like carrier bag material) and can be inflated with air.

Once inflated, the whole structure contracts and shortens like muscle does, and the cocktail sausage shapes becomes round like baubles.

There is considerable power generated by the artificial muscle and I watched as the University of Bristol researcher demonstrated that this can raise a robotic leg from a seated to a standing position.

Image copyright UNI Bristol Image caption The artificial muscles resemble long strings of cocktail sausages made from clear plastic

Another demonstration showed me a cuff of several air-filled long plastic sausages arranged around the knee area. Once inflated it became stiffer and more supportive to the knee. Prof Rossiter told me: "It means you can stand more comfortably."

"You need a cylinder of air in your back pocket and as you walk you get little 'phutts' of air as they actuate," said Rossiter.

They are potentially noisy to live with, but the vision the team is developing is one using electroactive polymers - materials that require electricity.

Prof Rossiter said this was "great, because you've got mobile phone batteries, lithium polymer batteries that you can put in your pocket".

He added: "With those, you have materials that you apply electricity to, and they contract like a muscle." And of course they would be silent.

Once incorporated into the trousers, there is scope for an embedded control system. The electroactive polymers themselves generate an electrical signal. Rossiter explains: "So we have this ability to measure someone's movement from the same materials that are also going to deliver the power to the person. The material is do the sensing, the computation, then they deliver the power to exactly the right place."

The technology might offer the potential of prolonged independent living, but a potential downside might be discouraging a person from using their own muscles, and then becoming weaker.

But as a rehabilitation device, it may be doing the opposite, Rossiter explains: "So that people who are weaker are becoming stronger, working with the device/trousers - they are exercise trousers making their legs stronger, their knees stronger."

Undoubtedly, the core technology has come on in leaps and bounds and they are putting it in to action. But the trousers are still just a pair of brightly coloured leggings - at least for the time being.

Style over substance?

They've also come up with air-driven waistbands to trousers which, at a push of a button, will allow trousers to loosen at the waist and drop to the floor. To great comic effect in the demo, but with real practical potential.

"People with functional incontinence just can't get to the toilet in time and end up using pads. That's a terrible change in their lifestyle, and we are trying to get around that as well," said Prof Rossiter.

The robotic clothes will need to be washable too.

And then there is the issue of style. It is debatable whether my 79-year-old dad, for example, would care to spend his time in multi-coloured Lycra. So they've got to look good - but to whose taste? This could mean that tights or other more discrete undergarments need to be developed with the technology.

Will they be hitting the high street soon?

"Our target is the kind of person that you or I, if we are relatively healthy, would become as we slowly get older," said Prof Rossiter

"The health service wants this. It is really good at realising that if you are going to interact with the human body, you probably want something that is soft... rather that one of these scary rigid exoskeletons."

The next phase of the team's work is going to involve working with clinicians, charities and prosthetic device companies.

Rossiter predicts that with the involvement of good design and manufacturing companies, the trousers could be available in 10 years.

But as Rossiter explained to BBC News: "It could be there is a smart knee-brace or a smart ankle brace or a smart pair of pants. So I see low-hanging fruit coming relatively quickly within a few years rather than having to wait for these actual trousers."

But first, there are quite a few problems remaining for these researchers to crack. Such as how to store enough energy in the trousers without it becoming too heavy and storing that energy for long periods of time. As Prof Rossiter points out "you don't want to walk up to the top of a hill and then find you can't get down the other side".