NARRATOR: Today, Yusuf is in Hertfordshire to meet Pollyanna, a 12-year-old girl with a love of ballet.
POLLYANNA: I first got into ballet when I was four. I want to be a dancer when I grow up.
NARRATOR: After losing her lower leg at the age of two, Pollyanna struggled to find a prosthetic leg that allows her to fully embrace her passion.
POLLYANNA: In my ballet exam, I got marks off because I didn't point my foot. But quite difficult to point your foot when you don't have a foot to point.
YUSUF: I know a lot about mechanical design and engineering, um and I just hope that I can apply that to dancing in a way that's gonna work for her.
NARRATOR: Since the age of two and a half, Pollyanna has undergone 21 operations. to stop her bone growing through her stump and has been fitted with over 20 prosthetic legs.
POLLYANNA: So this is my first one, and look at it compared to my leg now.
- Y: So how old were you when you had that one?
- P: Two.
- Y: Two?
- P: Two and a half.
- Y: Okay.
- P: Ish[?]. Oh two oh seven, Pollyanna. No.
- Y: Wow, you really have got quite a lot.
- P: Ah, number two.
YUSUF: This fix is unbelievably hard, but I have some ideas of different things that might work. I'm sure she'll tell me if it doesn't, so uh yeah, a lot to live up to.
NARRATOR: At the team's hub, Yusuf discusses the complexity of the case.
ROSS: That's mechanically the hardest thing that you could try and do with a prosthetic, right?
ZOE: If she's on a blade at the moment, really, it just needs to go a bit higher.
RYAN: Yeah, like a gas strut[?] in an office chair.
RYAN: That could actually be awesome.
ZOE: You know, you do a certain type of a click and it comes up, another one and it's down.
ROSS: I mean, this is a really exciting project because it's, like, really meaty technically, but then mechanically what we need to do is-, is so difficult. The human leg is an absolutely amazing bit of engineering, right, and-, and this is right on the limit of what the human leg can do, and we're trying to build a piece of technology that can do the same.
NARRATOR: Yusuf needs to know how Pollyanna currently dances with her prosthetic leg blade.
YUSUF: I'm hoping by the end of today, I have a real understanding of exactly what the leg needs to do.
NARRATOR: So he's heading to meet her and her ballet teacher, Miss Claire at a dance studio.
YUSUF: Hi, how are you doing? You must be Claire.
- C: Yes, nice to meet you.
- Y: Hi, nice to meet you. Heya, Pollyanna.
- P: Hello.
CLAIRE: And鈥 [music plays]I wouldn鈥檛 normally start point work until you're about thirteen, so what Pollyanna needs with the design of the dance leg is to have that ability to go up onto the balls of her feet, on demi-pointe and moving through-, through your feet as you move. But one-, her blade, when she goes up onto demi-pointe, her blade is only-, is made to measure the length of her foot when her foot is flat.
NARRATOR: In order for Yusuf to create a prosthetic limb that can extend to demi-pointe, he needs to start by taking precise measurements.
YUSUF: [music plays] Let's start with foot size. Okay. Light as a feather.We want something that's gonna just extend her length on one side, um that five to six centimetres, we have to ensure that it doesn't get in the way of her other leg, we have to ensure that the balance is right.
NARRATOR: Yusuf is [music plays] planning to create a prosthetic leg for ballet.
ROSS: Hey, how you doing?
- Y: Oh, you must be Ross.
- R: Yusuf, nice to meet you.
- W: Oh this is Yusuf.
NARRATOR: Poldark Prosthetics have developed a pressure casting system which allows them to take a perfect cast, exactly matching the upper leg. As she's still growing, Pollyanna needs around two socket fittings a year.
POLLYANNA: I like being cast; it's like being wrapped like a mummy.
MAN: Stand up please. Okay.
ROSS: We cast people in a standing position, which replicates the way the leg works and the shape of it when they're sort of running, dancing in Pollyanna's case.
[music plays]NARRATOR: The next step is to take a mould which is then cast into carbon fibre. This can hold Pollyanna's weight five times over.
RYAN: That's what you end up with.
- Y: There's one thing I'm not sure about. Can you change the colour?
- R: Yes.
- Y: Oh there we go.
- W: Can you?
- R: We can make it any colour you want.
- W: Can you make it pink?
- R: We can make it pink.
- W: Pollyanna, would you like a pink one?
- P: Oh yes.
YUSUF: The fit um is so important when you're dancing, you don't want it to be rubbing against your leg, you don't want to be uncomfortable, so now I鈥檝e got a socket, all I have to do is build the leg.
NARRATOR: Yusuf, who's working on Pollyanna's fix, has a brainwave on his way to work one morning.
YUSUF: Maybe I could use a dropper seat to actuate um Pollyanna's ankle joint. Um basically dropper seats are moveable seats, they move up and down and BMX cyclists use them quite frequently when they want to get the seat out of the way when they're climbing up a hill, or going over big jumps.So when you push the button, and you can get like uh electronic ones of these, it changes in height. But I wanna use this on Pollyanna's design.
NARRATOR: Yusuf's idea is to create a more lightweight leg, powered by a simple part from a bike.
YUSUF: Pollyanna's leg, um this is a-, a dropper seat when you press the button, you get that change in height.
M3 & M2: I like this.
M3: Simple but clever.
M2: How long do we have?
Y: Not long enough. [chuckles] It's definitely gonna be a challenge.
MAN 2: [music plays]
NARRATOR: Yusuf and the team begin building a prototype.
Man: If we make that too loose it's just gonna fly off-.
Man: It's gonna slide right off the end.
YUSUF: Well, that's not gonna work. What if we-, we use this to clamp it down.
- [?]: Good job.
- M3 & [?] Do you want a countdown?
- Y: Go on then.
- M3: Three, two, one. Wow! Look at that.
- Y: Look at that.
- [?]: The principle works.
- Y: The principle does work. Amazing. I think we've got the leg to test for Pollyanna.
MAN 3: [music plays]
YUSUF: Helloo.
- C: Hello, how are you?
- Y: I'm okay, I'm all right. I'm a little nervous, I'm not gonna lie.
- C: Have you got something to show us?
- Y: I do. Right. We've come up with a leg, now, it looks a little bit different. Pollyanna, what's your initial thoughts?
- P: Good.
- Y: Yeah?
- P: Yeah.Hopefully today's exercise will give us an opportunity to learn and figure out what to do next, so-.
- C: Okay.
- Y: So, how does that feel?
- P: Um, uh different.
So if you press the button now, it extends the length down, so if the movement works. So can you try this for me, Pollyanna. As you come down, just try and press the button. All of your weight's going down the foot. There you go.
CLAIRE: That's it.
- Y: There you go. So what do you make of the leg? Is there anything that you wanna improve?
- P: Well, the button, it's just really difficult to press.
- Y: Yup.
- P: Oh and the wire was a bit in the way.
- Y: Well, that's great feedback, I think I can take that away.
- P: Thank you for coming and doing the leg.
- Y: No problem. My pleasure.
YUSUF: It was a really useful day, there's quite a few things I still need to work out and resolve, but, the potential is there, and that's what I'm most excited about.
Follow the design process as an engineer tries to design a custom prosthetic leg for ballet.
Engineer, Yusuf Mohammed, takes up the challenge to build Polyanna a prosthetic leg with the required movement in the foot to point her feat.
12-year-old Pollyanna lost her leg in an accident when she was just two years old.
In the last ten years she has had 21 operations and been fitted with more than 20 different prosthetic legs as she has grown up.
Pollyanna has a determination not to let her disability hold her back from achieving her goals, including her dream of becoming a ballerina.
But the ballet world is unforgiving and Pollyanna has been marked down in exams for being unable to do moves that would involve her missing leg, including going up on her toes 鈥 or demi-pointe.
See how Yusuf researches and designs a new product to solve this complex engineering problem.
More from The Big Life Fix
Helping Ian to sail. video
Designers create new technology to help Ian who suffers from cerebral palsy
A smartphone fix to help Greg. video
A new mobile phone design helps with Greg's paralysis
Helping Ayala play. video
A new robot is designed to help Ayala play with her sister
The Big Life Fix
More clips and information from the television series
Helping Kyle follow his dream. video
A product designer creates a prosthetic to help Kyle cut hair
听