# Balls fly at inclination like the Earth

#### ChimpChimp

##### Semi-Pro
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

Last edited:

#### IowaGuy

##### Hall of Fame
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

Don't forget to factor in the Coriolis Effect

##### Legend
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

Don't forget to factor in the Coriolis Effect

I can't figure all this! No wonder I struggle with tennis.

##### G.O.A.T.
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?
So if I understand you correctly, what you’re saying is the earth isn’t flat after all?

#### Chas Tennis

##### G.O.A.T.
Get a high speed video camera and look at how your racket contacts the ball. A frame before impact, during impact and after impact can be very useful for understanding. One view behind looking along the ball's trajectory and another view from the side perpendicular to the ball's trajectory are two very good views for starters.

For considerably off centerline hits the racket may rotate in the hand and spray up or down.

#### SystemicAnomaly

##### Bionic Poster
So if I understand you correctly, what you’re saying is the earth isn’t flat after all?

And, apparently, it spins as well. All this time I had assumed that the sun, moon and stars were all circling around a stationary Earth.

#### SystemicAnomaly

##### Bionic Poster
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

Difficult to determine what the Earth is doing or what you are doing on your FHs w/o good HD, slow-mo videos of these events.

#### Dan R

##### Professional
Don't forget that all outdoor tennis courts are aligned north south, and so the rotation of the earth will cause you're ground strokes to deviate to the east. If you don't take that into effect you're screwed.

#### Morch Us

##### Professional
It is true that no-one hits the balls exactly to rotate 6 to 12. There is always a sidespin component (or the inclination you are talking about).

But is your diagram really correct? How can you hit the ball to rotate it that way?

I see the ball spinning at 4-10 direction. I am rightie.

Last edited:

#### Dou

##### Semi-Pro
When I watch slow motion video of ATP pros serving, I have noticed they do not have the classic back scratch position in their serve. Instead, it's like their arm drops straight back from the L position. It almost reminds me of a flat waiter's tray type motion. The palm is facing the side fence, then drops straight back, and catapults up.

It's hard to explain the exact difference I'm talking about, but Serena's serve looks more like one with the traditional back scratch position.

Does anyone else notice this? Can anyone articulate the difference better than I am?

Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

should be normal if you hit inside out on a fairly high ball.

##### Talk Tennis Guru
Don't forget that all outdoor tennis courts are aligned north south, and so the rotation of the earth will cause you're ground strokes to deviate to the east. If you don't take that into effect you're screwed.

Don't forget neutrino bombardment: my favorite excuse for UEs.

#### Pete Player

##### Hall of Fame
Forehand groundstrokes down the line fly at 6-12 o'clock direction.

I see the ball spinning at 4-10 direction. I am rightie.

The rotation axis of the Earth inclines at 23.4 degrees. Mine is like 40.

What does it tell? Contact point too far from or too much in front of the body?

The actual contact is happening more sideways, than it should. Taken, that you use the windscreen whiping method (whether you do or don’t), you start the swipe too early and end up brushing the ball to your left.

The racket face is ”off-line” as you make contact. Imprecise wrist action or orientation in general towards the target line.

——————————
On pain meds - all contributed matter and anti-matter subject to disclaimer

#### Dragy

##### Legend
Sidespin component is ok and even helpful. It’s natural to get more “hooking” spin on lower balls (Nadal banana shots at the extreme) and “fading”, outward drifting spin on high balls.

Replies
19
Views
9K
Replies
33
Views
4K
Replies
18
Views
6K
Replies
10
Views
1K
Replies
13
Views
1K