that pros use on their serve.

Some players and coaches call it serve pronation,

but that's only scratching the surface.

There are three keys that ATP servers use

to generate more power, spin and consistency

on their serves.

And just by learning this,

I was able to add 10 miles per hour to my own serve,

and I know that if you apply it,

it's gonna completely be a game changer.

Take a look at your favorite pro server

moments before contact.

What you'll notice is that they'll reach a position

where the racquet tip is pointing

to the back of the fence

while their hitting palm is pointing toward the side.

Then as we go through contact,

you'll see players start to rotate their racquet

in until it's facing the net naturally.

And this action of rotating your racquet into contact

in a counter-clockwise fashion

is gonna help to drive massive racquet head speed

into your shot.

Now, a lot of players do this,

but it's the way that it's executed

that separate the top servers in the world

from your average rec player.

So how should we go about executing

this serve pronation motion?

And should we let it happen naturally,

or should we try and manufacture it?

And also, if we have problems

like fixing the waiter's tray,

how do we simply let stuff like this happen naturally?

You see, the problem is if we don't understand

the deeper level biomechanics of what happens on the serve,

then we're actually gonna end up manufacturing

this pronation motion kind of like the forehand wrist lag.

So the first key to getting this motion down

is gonna be in your grip.

So for all of you guys out there who are trying to unlock

the power of this internal rotation,

we're gonna need to have some variation

of the continental grip.

Why?

Well, let's actually get into our continental grip here

on bevel number two,

and you'll notice that this creates a natural angle

in my racquet's grip and my forearm.

And now try the same motion,

but get into your Eastern grip like this,

or what's more commonly called the pancake grip.

You see the problem with this motion

is that with the pancake grip,

you're not able to put the blueberries on the syrup

and then, you know, your pancakes get all soggy.

And therefore, when you're actually getting into

your eating process-

- [Man] We're talking about serve here.

- Oh yeah, that's right.

(laughs)

I was hungry.

So going back to the Eastern grip,

whenever we have a milder grip,

this is actually gonna decrease the angle

that we have between our forearm and our racquet,

and therefore, when we start to do

this poor pronation motion,

this is only gonna help to turn the racquet over

instead of with the continental grip

helping to drive it forward.

Now, because you can't internally rotate in this case,

what do you do instead?

Well, we end up dragging our arm forward to contact,

which gives you that feeling of arming the ball,

or we end up just settling for a triceps exention motion,

which makes you feel like you're pushing the ball.

In either case, you're feeling tight.

Like you need to put a lot of effort into the shot

with less results.

So with the continental grip,

not only will you increase your power,

but you'll also be able to create that natural topspin

that's gonna give you that crazy kick and sick spin

that we'll cover soon.

Key number two is the pro drop position.

Coined by John Yandell over at tennisplayer.net,

this is the position where the racquet tip

is gonna swing all the way out

to the right edge of your body

until it's parallel to the trunk

if you view it from this angle.

This position is gonna give you

that full external rotation in both your shoulder

and your forearm, and it's gonna mark the end

of your racquet drop.

With this motion, you're gonna be able to execute

and utilize that powerful internal rotation

to get that maximum effect on the ball.

Now, anatomically, this is gonna put a stretch

on your internal shoulder rotation muscles

in the same way that a baseball pitcher

will be able to flip their arm back

before releasing the ball.

And this is also why making sure you have

the correct loading techniques

and engaging the right prime muscle movers into your shot

is really key for this.

According to a study done

by Dr. Bruce Elliott and colleagues,

the hitting arm is responsible for over 80%

of the racquet head speed you're gonna generate at contact,

but this isn't necessarily where all the power is generated.

Another article by Dr. Mark Kovacs

shows that over 50% of the force on the serve

is actually gonna come from something called

the leg hip kinetic chain sequencing.

So here, top pros accelerate

by driving their legs through the ground,

and that's gonna help to propel their hips and trunks

to explosively rotate into the net,

and then that's going to, with a relaxed hitting arm,

help to flip your arm back and down,

creating that nice stretch on your rotator muscles

to actually drive it back into contact.

And going into the upward swing,

top pros are gonna continue this external rotation motion,

giving them the appearance of leading

with the edge of the racquet before boom,

rotating into contact.

Now you can easily contrast this with going around

at your local club and taking a look

at how the majority of players execute their service motion.

What you'll notice is that,

instead of leading with their racquet edge,

they'll actually lead with their racquet strings.

And because of issues like we talked about with the grip

and other techniques like the waiter's tray issue,

players find themselves often feeling that pushing effect,

because they're not able to achieve the full foot motion

by getting into the pro drop position.

And again, if you don't pre-stretch

your hitting shoulder prior to contact,

then there's no way that you can actually

maximize the effects of this pronation motion,

unless you've got big old forums like Popeye or something.

(laughs)

And to execute this technique of leading up with the edge,

watch Daisha's video here.

Now, because pros have delayed this pronation effect

until the few milliseconds before contact,

they're forced to execute this motion a lot faster

and more explosively, leading to the amount of power

that you see on the tour.

All right, ladies and gentlemen,

we've reached the moment of truth.

Players here are gonna start rotating their racquet

in through contact with this pronation motion.

Now on the surface, this motion doesn't really sound

very intuitive, does it?

I would much rather personally hit with my entire arm

than have to like rotate it with this weird motion.

And this is also where players end up getting tripped up

and manufacturing the pronation,

and then worse, end up getting injured

like I did at one point.

So instead, it's pretty clear that we're gonna need

a step-by-step framework to make this happen.

According to Dr. Elliott's study, at the highest level,

this so-called pronation force

is actually gonna come from internal shoulder rotation.

Biomechanically, pronation is actually just

the independent rotation of the forearm.

The way you can tell this is by

grabbing your racquet in your hand

and put your elbow to your side.

This way, internal rotation

is not gonna be necessary here,

but instead, just rotate your forearm back and forth.

This motion of the racquet strings going from up to down

is pronation.

So if that's what pronation is,

then how am I expected to generate all this force

from just these little forearms here?

And that's exactly what elite servers figured out.

Pronation is actually only responsible

for 5% of the total racquet head speed that you get.

But another motion actually generates

over 50% of your power.

It rotates your humerus bone in your upper arm

and is propelled by muscles like your chest,

lats, other muscles in your shoulder, your back,

your infraspinatus.

It's called internal shoulder rotation.

(laughs)

So you might be wondering how does all of this

tie into your serve?

Psychologically, I found it personally very helpful

along with a lot of students of mine,

to think of a concept called long axis rotation.

This refers to the unitary rotation of both your shoulder

and your forearm.

And this is gonna help to turn your racquet over

with way more power than you ever experienced before.

And as we'll cover in future videos,

this is not exclusive on just the flat serve.

In fact, you still are gonna get that rotation motion

from the shoulder on the kick and the slice,

but because of a few changes in the forearm,

that's gonna change the direction of racquet head speed,

that's gonna affect the ball differently.

And that's a little sneak peek for you there.

Henry, a deal is a deal.

(laughs)

Now so far, we talked about the common threads

that all top servers use moments before contact.

But after contact, things start to get

a little bit complicated.

Sampras is gonna continue to rotate his racquet

through contact until his racquet and hitting palm

are facing the right side of the fence,

and his arm will actually bend

and his hand will stay above his hitting shoulder.

Federer rotates his racquet through just as well,

except he actually does it a little bit slower,

and he completes his hitting arm rotation

when his hitting hand comes to about his hitting shoulder.

Now, Murray, he doesn't execute nearly as much

of this rotation motion from the shoulder,

but instead brings his entire arm down with the racquet face

and the hitting palm facing the court.

Now, Nishikori also doesn't have

too much of this rotation through,

but he also bends at his wrist instead of snapping his elbow

like Sampras would do.

But most of them will rotate their racquet head

until it's facing the hitting side of the fence.

And this makes sense because, you know,

if over 50% of the racquet head speed

comes from this motion, then it wouldn't make any sense

if we slowed it down right before contact, right?

Think about a professional sprinter.

And if they were to like, right before the finish line,

decelerate at its final pivotal moments,

you're actually going to be slowing down

at the most critical moments of the shot itself.

So you won't have as much space to accelerate through

and thus, you won't have more power.