[Man] Set.

Go!

The title for the fastest man or woman on earth

belongs to whoever owns the 100 meter sprint time.

Why?

Because it is the benchmark for all out running speed.

[Broadcast Announcer] And off and running.

Asafa Powell gets a good start.

Usain Bolt in the middle is now exploding!

Jamaican sprinter Usain Bolt is the fastest man on earth

with an official world record time

of 9.58 seconds in the 100 meter dash.

At his fastest, he's running more than 27 miles per hour.

Elite sprinters look like they leave it all on the track,

but could they eke out just a little bit more, somehow?

Today we're gonna look at why running

a 100 meter dash in nine seconds flat is almost impossible.

To find out what it takes I towed the line

with two of America's top sprinters,

ran on an absurd treadmill,

and talked physiological limits with a biomechanist.

The determinants of how fast

you can complete a 100 meters

are how quickly you get up to speed,

and then how fast you can run once you get there basically.

Yeah, make sure they're all the way on.

All the way on the sides.

Alright.

I got a lesson in getting up to speed

from two of the fastest runners on earth,

Mike Rodgers and Bryce Robinson.

And then for the setup,

obviously you want your fingers behind the line.

Rodgers, an olympian,

has clocked a 9.85 second 100 meter time.

Robinson, a rising track star,

is also one of the few sprinters

to have run the 100 meter dash in under 10 seconds.

They showed me how to set up the blocks for a good start.

It was only so much help.

Go!

[laughing]

[Robbie] Okay, what did I do right?

You came out the blocks, you did that.

You got in correctly.

Pushed out.

Pushed out.

But the release from the pedals,

you gotta work on that part.

Set.

[Robbie] I was basically falling forward and flailing.

[laughing]

When you got out you looked straight up.

See, yeah.

The step, trying to catch yourself, which is normal.

Passed class one, this is class two.

Push out, Bryce.

See?

So he's dragging his back foot.

That foot drag forces Robinson to keep

his rear foot planted on the block longer

and that gives him a more explosive start.

He also swings his arms for maximum power.

The drag comes in because you're trying

to push off this thing as long as you can.

You don't wanna step off this thing without pushing.

This time I'm gonna set up

exactly how I did the first time.

I'll get set, and then I'm gonna focus on two things.

One is gonna be this toe drag

coming off on my left foot, right?

'Cause I wanna be on that block for as long as possible.

And that kinda forces me to do that.

That also has a secondary effect of keeping me lower, right?

Yeah. Yes.

And the third thing I'm gonna focus on is moving my arms.

Go!

[grunting]

[laughing]

That was better than the first time.

After the lesson I asked them to race.

But it was early in the season

and these guys weren't about to blow out a hamstring

going full tilt for 100 meters against a guy like me.

But as you can see they really didn't have to.

They had me beat the moment we left the blocks.

They weren't even trying, which is obvious.

They're two of the fastest people on earth.

But why are they so fast?

Really great position.

[Robbie] To find out I talked to this guy.

Front side, the heel recovery

issues are almost irrelevant.

I'm Peter Weyand.

I'm the director of the Locomotor Performance Lab

here at SMU where we study the mechanical

and physiological basis of human performance.

[Robbie] He invites world-class

athletes like Robinson and Rodgers,

and not so world-class athletes like me

to run and be studied at his lab in Dallas.

How?

With a lot of really cool and really expensive equipment.

We have some high-tech custom toys,

a force instrumented treadmill and ultra-high speed cameras

with motion detection capabilities that are very precise.

[Robbie] His research shows

that the key to elite sprinting

is how much force you can put into the ground and how fast.

Usain Bolt or another elite male sprinter

at top speed will put down five times their body weight,

typically in .09 seconds or nine hundredths of a second.

If a person can put out those kinds of forces

they have a shot at earning a place

on the lab's record board.

These are the records,

so 11.72 for a guy, that's cooking.

It's smoking, yeah.

Do you know about what that

translates to in miles per hour?

[Peter] Just under 27.

Holy cow!

That's amazing.

What's a respectable,

and you're not being polite?

I would anything, you know eight,

eight and a half would be pretty respectable.

We're gonna shoot for respectable.

Got my socks.

Speaking of respectability,

Weyand had me put on a ridiculously tight outfit.

Let's go do it.

Then I got marked up with infrared dots,

and strapped into a safety harness

to run on the lab's force-sensing treadmill.

Why the harness?

Just listen to this thing.

[treadmill whirring]

It sounds like a jet taking off.

It can go 90 miles per hour.

Weyand had me warm up, first with a jog.

Then he had me run at four meters per second,

that's about an eight minute mile, five meters per second,

about a five and a half minute mile, and then.

So this treadmill is moving at 6.7 meters per second.

That translates to exactly 15 miles per hour,

which translates exactly to a four-minute mile pace.

I got to feel like Roger Bannister for about two seconds.

[Peter] Whenever you're ready, Robbie.

[Robbie] Finally, I topped out at eight meters per second,

which is just shy of 18 miles per hour.

[Peter] Good!

That's right at the threshold. [laughs]

We have the treadmill set to 8.1 meters per second.

Yeah.

I was doing my best to keep up with it,

but I was drifting back a little bit.

Drifted, I think we said 20 centimeters,

which means I was actually running at around eight flat.

Right about.

Okay, so how does that compare to a world-class sprinter?

So, not bad, not bad.

It's a respectable speed.

An elite sprinter, a male,

will hit somewhere around 11 and a half or so.

Fastest ever recorded speed is 12.4 from Usain Bolt,

12.4 meters per second.

[Robbie] That kind of speed is what propelled Bolt

to his world record time of 9.58 seconds.

[Broadcast Announcer] The 100 meter dash.

[Robbie] But 50 years ago the great barrier for

sprinting was a 10-second 100 meter dash.

[Broadcast Announcer] Sprinters to win,

equaling the world record of 10 seconds flat.

[Robbie] In 1968 American Jim Hines burst

across the line in 9.95 seconds.

His record stood for 15 years.

Since then sprinters have been whittling

away hundredths of a second at a time,

track surfaces have improved, training's gotten better,

and sprinters these days wear these really tight outfits.

That helps with wind resistance.

As athletes seek every advantage,

timing and verification technology

have also gotten more sophisticated.

Any record set with a tailwind greater

than two meters per second doesn't count.

But Weyand says there aren't many

ways for athletes to get faster.

That's because of basic physics.

Sort of in big picture science how fast humans can run,

100 meters is really

it's all force in relation to body mass.

So we use use the analogy of athletes

as being force application machines.

Force in relation to mass is what determines

how quickly a sprinter can accelerate.

It's what determines their top speed.

There are intrinsic constraints on force.

Remember, it's all about maximizing your force

in as little time as possible.

Let's look at how that concept applies

over the course of a race, starting in the blocks.

So there's the initial push out of the blocks,

which is really dependent upon athletes'

muscular force or strength capabilities.

And they get up to almost 1/3 of their top speed

before their foot initially hits the ground.

So by far that's the greatest portion of acceleration.

[Robbie] I saw this happen firsthand as Robinson

and Rodgers blasted away from the start line and from me.

And then there's a transition phase

where what they do step to step changes

a little bit in terms of how much force they can apply,

they can apply progressively more

as they go step by step further into the race.

But they're typically by step 12 or so

they're at 85, 90% of their max speed.

It doesn't take very long.

[Robbie] That max speed is what Weyand

examines in short bursts at his lab.

And there the mechanical determinate

is no longer sort of their intrinsic strength,

but rather it's the motion,

it's that their mechanics or technique of sprinting

to drive the limb down into the ground forcefully.

They essentially throw a quick, sharp punch at the ground

and that maximizes their force capabilities.

Then the last 30 meters of the

race they typically slow down.

They do so simply because muscle fatigues very rapidly,

and the period of time that they can sustain

their top speed is very short.

It's less than a couple of seconds.

[Robbie] Weyand looks at the forces an

athlete applies during their run,

and it's in these numbers you can really see

why an elite sprinter is so much faster.

Once they get rolling the force on the ground,

and again what they're better at doing than everyone else

is applying force in the time available,

the force on the ground becomes a motion based mechanism

where they use their limbs to throw a punch at the ground.

Let's look at how much more of

a punch a pro can give the ground.

On the left is me running at 7.82 meters per second.

On the right is Robinson doing 10.85 meters per second.

I'm hitting the ground as hard

as I can to keep up with the treadmill

with a force roughly three times my body weight.

Robinson weighs about as much as I do,

but he's throwing almost five times

his body weight at the ground,

and he's doing it way faster than I can.

And that weight is key.

Look what happens when you take away gravity.

This is Usain Bolt running in a microgravity airplane,

and even he can't generate any push.

Back on Earth that raw strength has

to be precisely applied to the track, and that's form.

Look at how much higher Robinson brings

his heels and his knees on each stride.

Those mechanics are what allow him to maximize

the force his legs deliver to the ground

and clock 100 meter times just under 10 seconds.

Of course he'd like to get even faster.

When you're training this season

is there a benchmark you're shooting for,

or are you just kinda trying to get the best you can?

Man, I really want to run 9.8 this year,

this upcoming year.

If, God willing, it's faster than that I'll be happy,

but I really want to run a 9.8.

The main goal is to run 9.9s consistently.

I run 9.9s consistently then that 9.8

will pop out there, at some point it will.

[Robbie] But what if a sprinter wanted

to go a lot faster, say nine seconds flat?

Weyand's research shows that the human body

would have to exert forces greater

than have ever been recorded,

at speeds that probably aren't possible.

So typically at top speed

they'll put a force into the ground that

peaks at five times their body weight,

and they'll have a foot ground contact

time or period of force application

that's typically .09 seconds or nine hundredths of a second

on the very short end .085 seconds.

To get to what would be required for nine flat

they would have to approach six times body weight

and a foot ground contact time

of just over seven hundredths of a second.

So we're not gonna see anyone blast

across the line in nine seconds in the 100 meter dash.

But that doesn't mean a sprinter couldn't

cover that distance that fast.

In fact, some of them already have.

So if you remove the acceleration requirement

from a stationary start from the race

and you allow a flying start coming in

humans are comfortably under the

nine second barrier already.

World record for four by 100 meter relay

held by the Jamaicans is about 36.7 or eight seconds.

So essentially each person after

the one that ran the opening leg

had to average nine flat for their 100 meter

segments for them to run that fast.

But the start is part of what makes

the 100 meter dash so thrilling.

Wait, on that last run you were

first out of the blocks by a mile.

And then you were ahead of me,

and I was bringing up the rear.

Yeah. Yeah.

So, yeah, right out of the blocks

you guys are both beating me really fast.

That's nuts.

Now, some of that has to do with their raw strength,

but it also has to do with their incredible reaction times.

So do you practice on reaction time stuff at all?

We do.

[Robbie] Under current rules,

if a sprinter moves before the starting gun,

they're automatically disqualified.

This actually happened to Usain Bolt

at the World Championships in 2011.

What I like to do is close my eyes,

and first thing I hear I move.

Basically, that'll help you alleviate

false starts and stuff like that.

You don't hear nothing you don't move.

[Robbie] But here's the thing,

an athlete can also be disqualified

for leaving the blocks less than a tenth

of a second after the gun goes off.

The reasoning is that a reaction time

of less than .1 seconds is physiologically impossible.

But research shows some sprinters may

actually be capable of reaction times

as quick as point .08 seconds.

I close my eyes 'cause I used to keep 'em open

and people flinch and do all that, all the weird stuff.

I feel like I'm a pretty aware person,

so I kinda notice that stuff.

I'll be hesitant to go because of it.

So what is actually possible for the 100 meter dash?

And does anybody stand a chance at breaking Bolt's record?

I would say if you put together a perfect human being

who's you know exceptional, and a perfect race,

I think certainly something in the 9.40 range,

low 9.40s, maybe a little bit faster than that

under currently legal conditions should be possible.

So keep watching.

We're probably never gonna see a nine second 100 meter dash.

But remember that what these athletes

are doing is already almost impossible.

[soft rock music]