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?
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.
三年前 英国单板滑雪运动员Billy Morgan完成了世界上第一个向后歪轴转体四周
Three years ago British snowboarder Billy Morgan pulled off the world’s first quad cork.
Morgan will be at the Olympics as well Andri Ragettli.
而去年 Andri Ragettli成为第一个在双板上完成这个动作的人
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.
Ragettli’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 cork screws.
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, a try.
Emphasis on try?
But getting that quad done perfect
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 six tenths 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.
If you’ve ever seen the skaters spin you’ve got the idea.
They start with their arms extended.
And then 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 skaters’ 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 them before you make contact with the ice,
which soften the rotation under the definition of the landing.
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 in the University of Delaware.
I worked with the United States Figure Skating
to assist coaches and skaters,
and performing multiple revolution jumps.
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.
We 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 failed in the air.
They adopt the position that doesn’t enable them
to spin as fast as they need to complete the jump.
To learn what that kind of rotation feels like
I got some help from Tim Goebel.
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 king until Nathan Chen came along and unseated me.
So what did it take to become the quad king?
I think it took a lack of fear and probably a little stupidity.
And some time on the trampoline,
which skaters use to practice their jumps.
I mean you’ve got more hang time 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.
I’m all about less wear and tear on the body.
So just one easy turn.
And Goebel made it look pretty easy.
But for me, a totally different story.
Tim gave me a lot of pointers on how to engage my core
and spin more efficiently.
-Right arm is out.-Right arm is out.
Core is engaged.
-All right. -Well done my friend.
Three to go!
I asked him to time me while I went for my magnificent spin and a half.
Well you’ve got enough hang time to successfully complete a quad.
– I get enough hang time to successfully…- So that’s impressive.
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 its grace
is a brutal sport.
Researchers at Brigham Young University
actually attached sensors to skates
to record the impact forces of landing big jumps.
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.
Even on the safety of a trampoline
there was no way I was ever gonna
pull off a quad like the elite skaters,
if I couldn’t spin faster.
If they are going to successfully land a quad,
peak rotation velocity going to have to be 400 rpm.
To pull off 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 volecity closer to 500rpm.
The highest we have 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.
And then I brought it into work
for my co-workers to try.
Pretty sure none of us got anywhere close to hitting 400rpm
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
Sara Ridge和Jim Richards 让运动员们
Sara Ridge and Jim Richards had athletes
wear them while performing jump spins.
I’m going to show you why
from the safety of this chair.
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 rotation.
All that’s left is you’re going to increase your rotation speed.
And it works.
At least for the first few jumps.
All of the skaters were over rotated which meant
that the gloves are 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 any time 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 can 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 year’s 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.