(fast percussion)

[Robbie] This is the year of the quad.

Since the last Olympic Games, snowboarders and skiers

have perfected a trick called the quad cork.

Which, looks and sounds ridiculous, because it is.

It's five full spins, and four full flips,

all in the span of about three seconds.

But you know who spins a lot faster

than that, in way less time?

Figure skaters.

We're gonna find out what it takes to spin your body

four times in the air in a fraction of a second.

And why spinning five times could be almost impossible.

Three years ago, British snowboarder Billy Morgan

pulled off the world's first quad cork.

Morgan will be at the Olympics,

as will Andrew Ridgeley, who last year became the first

person to do a quad cork on skis.

Mind you, these are some of the world's best athletes.

Ridgeley's crazy parkour workout went viral this fall,

because it's like a superhuman Rube Goldberg, in the gym.

But only a few years ago, skiers and snowboarders

weren't even sure the quad cork was possible.

Which raises an interesting question.

Are we at the limit of how much

a human can turn and flip through the air?

As amazing as the quad cork is, it might not be the limit.

One physicist calculated that a boarder could actually

complete six or more corkscrews.

That's because snowboarders and skiers get

hang times of close to three seconds.

That may not sound like much, but it is a lot of time

to a figure skater like 16-year-old Dinh Tran.

He's an up-and-coming skater in San Francisco.

He took home the silver at junior nationals this year.

So you're here today to practice quads, right?

Yeah. Yeah?

Yeah, I try.

Yeah? Yeah.

[Robbie] Emphasis on try?

[Dinh] Yeah.

[Robbie] But getting that quad down perfect, is tough.

Dinh and other skaters don't get a ramp to launch from.

They have only their leg muscles to propel them

about a foot-and-a-half off the ice.

And then they've got just about

6/10 of a second to rotate and land.

It's one really big fast motion,

so you jump up in the air, and then you kind of pull

your arms in and your legs in at the same time.

[Robbie] If you've ever seen a skater spin,

you've got the idea.

They start with their arms extended, and as they

pull their arms in, it causes the rotation to speed up.

Same thing when they're in the air.

That's because of something called

the conservation of angular momentum.

Angular momentum depends on both the speed

of the skaters rotation, and the position of

the skater's body, relative to the axis.

That's the center of their rotation.

The closer the body parts are to the axis of rotation,

the faster they spin.

And then of course, there's the landing.

Or you have to open up before you make contact

with the ice, which stops the rotation

and it dampens the landing.

[Robbie] Quads have become pretty much

mandatory for the top male skaters.

Thanks, in part, to US national champion Nathan Chen.

The first man to land five of them in one program.

To get a better sense of what it takes, I bounced

with an Olympic skater, got insanely dizzy on this thing,

and talked revolutions per minute with this guy.

My name is Jim Richards.

I'm a professor at the University of Delaware.

I work with United States Figure Skating to assist

coaches and skaters in performing

multiple revolution jumps.

[Robbie] Richards is a professor of kinesiology.

And he uses motion capture technology to map jumps

and help correct slight imbalances that can

throw off even elite skaters.

[Richards] I learned a long time ago that most

of the skaters jump high enough.

And most of them leave the ice with enough angular

momentum to complete the jump.

But, most of them fail in the air.

They adopt a position that doesn't enable them

to spin as fast as they need to to complete the jump.

[Robbie] To learn what that kind of rotation feels like,

I got some help from Tim Gable.

He was the first american to land a quad in competition,

and did three of them on his way to a bronze

medal at the 2002 Olympics.

They called him the quad king.

You're actually known as the quad king, right?

I was the quad kind until Nathan Chen

came along and unsuited me.

So what did it take to become the quad king?

I think it took a lack of fear,

and probably a little stupidity.

[Robbie] And some time on the trampoline,

which skaters use to practice their jumps.

[Tim] I mean, you got more hangtime on a trampoline.

You can experiment with the technique

and the air position a little bit more.

With a lot less wear and tear on your body.

[Robbie] I'm all about less wear and tear on the body.

[Tim] So, just one easy turn.

[Robbie] And Gable made it look pretty easy.

But for me, totally different story.

Tim gave me a lot of pointers on how

to engage my core, and spin more efficiently.

[Tim] Right arm is out.

Right arm is out.

Core is engaged.

And turn.

Alright.

Well done my friend.

Three to go.

I asked him to time me while I went

for my magnificent spin-and-a-half.

And one point oh eight.

Well, you got enough hang time to

successfully complete a quad, so.

I get enough hang time to successfully...

That's impressive

[Robbie] Even after dozens of jumps, I never made it

to even two revolutions, much less four.

One of the reasons to train on a trampoline

is that ice skating, for all it's grace, is a brutal sport.

Researchers at Brigham Young University

actually attached sensors to skates to record

the impact forces of landing big jumps.

[Sarah] From the data that we've collected with the

instrumented blade, we found that skaters land with

somewhere between five to eight times their body weight.

[Robbie] Even on the safety of trampoline,

there was no way I was ever gonna pull of a quad like

the elite skaters if I couldn't spin faster.

[Richards] If you're going to be successful in landing

a quad, peak rotation velocity is going

to have to be 400 RPM or higher.

That's crazy.

To pull of a quint would involve even faster speeds.

So fast that Richards doesn't really think they're possible.

In order to land the quint, which puts their average

rotation velocity around 400 RPM, that would put their

peak rotation velocity closer to 500 RPM.

Wow.

So the highest we've ever actually seen

is about 430, 440, in that range.

So, you remember how pulling your arms in can

actually make you spin faster?

There's a way to practice that at home.

It's with one of these things,

it's called a gold medal pro spin trainer,

and it's basically a human turntable.

It is, per the instructions, for serious skaters.

So naturally, I tried practicing with it,

and basically just made myself sick.

Then I brought it into work for my co-workers to try.

Pretty sure none of us got anywhere

close to hitting 400 RPM, even if we all felt that way.

But there might be a way for professionals

to get the speeds they need to do a quint.

And that's with these.

They're weighted gloves.

And in an experiment, Sarah Ridge, and Jim Richards

had athletes wear them while performing jump-spins.

I'm gonna show you why from the safety of this chair.

[Sarah] So if you have a greater amount

of angular momentum, because your arms were out wide,

and because you had an extra mass further away

from your axis of rotation, once you're in the air,

and you bring your arms in, that extra mass

is that close to your axis of rotation,

all that's left is you're gonna

increase your rotation speed.

And it worked.

Kind of.

At least for the first few jumps,

all of the skaters were over-rotating,

which meant that the gloves were doing their job.

But after a few more jumps, all of the skaters adapted

back to spinning the way they did before the gloves.

But even if skaters could learn to use the weight

to their advantage, there's no guarantee that it would be

enough to spin them around five times.

Let alone that it would be legal.

So we're probably not gonna see a quint anytime soon.

And it's not hard to see why.

Spinning is absurdly difficult.

Even on a trampoline, getting twice the air

that the pros get, I could barely do it

one-and-a-half times, and it looked terrible.

Spinning even a little bit made me feel nauseous.

And I never even tried it out on the ice because

this place would not let me.

So at this years games, when you see people

spinning and they make it look really easy,

remember that it really, really, is not.

In fact, it's right at the edge of what is humanly possible.