🎾 19 - Stroke Commonalities I¶
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19 - Stroke Commonalities I — tài liệu 7 trang từ thư viện sách tennis.
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Tóm tắt nội dung (trích từ tài liệu gốc): Revolutionary Tennis Tennis That Makes Sense Step 6 Stroke Commonalities I: Lots Of Useful Stuff � Mark Papas mark@revolutionarytennis.com hit through the middle of the ball 2 directions for 1 contact ultimate striking theory racket acceleration Everyone wants a faster, or quicker, stroke. Everyone wants to hit a heavy ball, hit it hard, place it well, and do it all consistently. And no one wants to work too hard to achieve these results. To enhance stroke speed with a pattern that can be repeated consistently with the least amount of work, what matters is how your arm and racket and stroke ar
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Revolutionary Tennis
Tennis That Makes Sense
Step 6
Stroke Commonalities I:
Lots Of Useful Stuff
� Mark Papas
mark@revolutionarytennis.com
hit through the middle of the ball
2 directions for 1 contact
ultimate striking theory
racket acceleration
Everyone wants a faster, or quicker, stroke. Everyone wants to hit a heavy ball, hit it hard, place
it well, and do it all consistently. And no one wants to work too hard to achieve these results. To
enhance stroke speed with a pattern that can be repeated consistently with the least amount of
work, what matters is how your arm and racket and stroke are configured the moment you strike
the ball, not what your stroke looks like after you've hit the ball.
In order to form a stroke pattern mentioned above, I'm assuming you've moved into the ball with
four steps (Steps 1, 2) to place the contact between the width of the feet (Step 3) and transfer
power with linear momentum (Step 4) while keeping centered and balanced (Step 5).
HIT THROUGH THE MIDDLE OF THE BALL
You've been told that hitting through the middle of
the ball produces head-on contact for power and
control, but the popular stroking direction in books
and tennis tips produces the opposite effect.
The popular stroking direction you've seen before is
an arrow either perpendicular to the net, 6A, or
drawn down the middle of a street. The caption
states the stroke's direction follows this arrow with
the racket parallel to the net at contact, but this
direction produces miss-hits.
IT'S SIMPLE GEOMETRY
It's true that what you learn in school becomes useful in adulthood. Especially math.
The middle of a round ball lies in a number of directions, but when it's moving the middle lies per
the direction in which it's moving (center of mass in motion). Think of head-on contact between
a ball and racket as two cars in a head-on collision. From one direction comes a tennis ball, from
another a tennis racket face, and they both impact head-on, or squarely.
A tennis ball moves on an angle across the court, Step 1. Hitting through the middle of a tennis
ball, then, means a stroke direction against, or into, the ball's incoming angle.
Let's transfer this image to a 2 dimensional bird's eye
view used before, 6B. The stroke's direction through
the middle of the ball is to be drawn per the ball's
flight line, not perpendicular to the net.
To ensure head-on contact, the racket face forms a
right angle at contact to the ball's flight line. In 3
dimensions you have topspin and slice, but they too hit
head-on with either an open or closed racket face for
solid contact.
Swinging straight to and/or keeping the racket face
parallel to the net doesn't place the ball and racket in a
head-on collision. Your stroke is unsupported and
weaker with this popular idea.
2 DIRECTIONS FOR 1 CONTACT
You may have figured this out on your own, what I think
could be the most meaningful secret to the game. When
you shift your weight linearly into the contact spot, Step
4, and the stroke pattern heads through the middle of the
ball toward the opponent's side of the court, 6B, 2
distinct directions are involved. Diagram 6C combines
these 2 directions.
You shift your weight into the contact spot, into the ball;
the stroke heads through the middle of the ball toward
your opponent. 2 directions for each contact.
Your body shifts weight for power in tennis using linear momentum, not angular momentum
(rotating the hips/shoulders), Step 4. You shift linearly into the ball and not "linearly" with the
ball's flight to the opponent's court.
Now the example of hitting a ball on-the-run comes into sharper focus. 2 clear and distinct
directions are involved for body and stroke hitting on-the-run moving either forward into the
court or off the side. The empowerment structure (body) heads into the ball/contact, and the
delivery structure (stroke) heads towards the other side of the net.
I'm aware that the body's extra momentum when hitting on-the-run covers up a host of sins. But I
believe extreme examples often provide insight, as this example has for movement, footwork,
contact zone, and power delivery methods in earlier Steps. After all, when you start a rally by
bouncing and stepping into the ball, you're enacting 2 direction for 1 contact, on a slower basis.
� Mark Papas Step 6 p.2 /7
WHAT ABOUT BODY ROTATION DURING THE SWING?
The swing has the potential of ruining the body's foundation and support, Step 5. Its angular
momentum and acceleration can pull the body away from the ball prior to and during contact
because it heads in a direction separate from the body's focus (into the ball/contact).
The swing's trajectory is basically an arc that stems from a common origin (shoulder). Arcs
accelerate in a direction inward from the trajectory, that is inward from the contact spot, 6D,
which is why 6B's head-on stroking direction feels solid and strong. This sends the ball back in
the same direction, often more to that one side.
There are times when you send the ball outward from the contact
spot. Here the shot is weaker and the risk of losing control is
greater: hitting inside-out, changing the ball's direction (though Step
7 explains when changing the ball's direction plays to the stroke's
strength), or responding to a sharply crosscourt ball (unless you hit it
even more sharply crosscourt). Generally speaking, hit your best
shot, through the middle of the ball. If you choose not to,
understand the risk involved and don't go all out.
If the body rotates after the contact it's okay. This happens, the
body doesn't remain still like a statue, the stroke pulls at you.
However, if the body rotates during the swing, during contact as part
of the swing for power, both power and control are sacrificed. You need to separate the
empowerment structure from the delivery structure.
ULTIMATE STRIKING THEORY
The ultimate striking theory is simply understood. Boxers and martial artists train to generate a
large a burst of energy over a small period of time and space. No large, looping, roundhouse
punches for these athletes, but short, compact, deep, effective strikes. Quick. Heavy.
Earlier I've used the example of Muhammad Ali's "invisible" knockout punch over Sonny Liston,
and Bruce Lee's two-inch punch (or however small in length it really was). By the same token,
you don't need a large bomb to deliver the biggest of bangs anymore.
The ultimate strike is not of great length, and its force extends beyond its target. Ball placement
has always been considered the target in tennis, but it's the second target, if not the objective.
The first and primary target is and has always been the ball at contact. A tennis player focuses
everything s/he does into the contact, footwork, power, vision, stroke, and then places the ball.
BEYOND THE BALL
I haven't personally broken any bricks or boards with my hands, but martial artists say they focus
not on the top surface of the board but beyond it, past it. When breaking through cinder blocks
stacked on top of one another, the athlete focuses on a point beyond the last block.
Furthermore, a martial artist focuses on the forward strike's acceleration, creating a burst of
energy to break the blocks.
� Mark Papas Step 6 p.3 /7
You are about to strike a tennis ball with the racket
strings. What will your strings focus on, the ball's
surface facing you? Focus beyond the ball, past the
ball, on the side away from you, 6E. Do you take that
racket really far back to increase your power? No
need to, just take it back quietly. When you swing,
will it be a long swing for more oomph? No need to,
just a burst of energy into the ball.
A popular tennis idea wants you to hit through three
tennis balls instead of one to hit "through" the ball. This image still has you focusing on the ball's
surface facing you. Instead, focus beyond the ball for greater effect.
RACKET ACCELERATION
Step 5 said: "To help the swing accelerate and enjoy the most strength and support from the
body, the body doesn't move. Except for the swinging arm, of course. Your front shoulder
remains still up through contact, 5J, acting as a brake against the force of the stroke to accelerate
it. Rotation, besides moving you away from the ball and being a complicated power source
unnecessary for tennis, creates friction during the swing and slows it down.
Now we'll add up what we've learned here in Step 6. A stroke's acceleration lies in a direction
inward from the contact spot, 6D, and is greatest when there is a common origin, our shoulder
and then elbow, in our case. [Extend your arm straight away from your body, keep your shoulder
still, and swing the arm side to side. Next, move your shoulder side to side and swing the arm.
Compare the two speeds. When the common point, the shoulder, is still, the arm accelerates
more. Furthermore, the arm pivots around this common point.]
When you swing the racket and move the shoulder(s) around you lose acceleration because the
common point moves. The same happens when you shift your weight along the flight line of the
ball, or when you rotate, the common point moves. I've said it before, and I'll say it again:
Rotation for tennis players is counterproductive to success.
DON'T BE A STROKE GUZZLER
Don't be a stroke guzzler. The idea is not to waste a natural resource, the arm, like an inefficient
automobile engine wastes gasoline. You become a stroke guzzler when the arm moves too much
as a whole, or when the arm is engaged as one unit or doesn't flex during the swing.
Let's use the same example above where you extended the arm straight away from you and
moved it side to side keeping the shoulder still. Do it again and notice the speed at which your
hand moves. Stop, then bring the elbow in to touch your stomach and move only the forearm side
to side. The hand moves faster, doesn't it?
During a tennis stroke the shoulder is the first common point but you can't swing the racket with
your arm completely extended or straight and expect good results. It's too slow, plus there's no
leverage with the arm this way. You don't pick up a box with your arms straight, do you?
The elbow, then, becomes a second common point, or pivot point, during your swing. As you
� Mark Papas Step 6 p.4 /7
begin your forward swing the arm bends to pivot at the elbow, bringing the elbow in closer to the
side of your body, and the biceps slows down. Here the shoulder relinquishes its role as the
common point and passes the torch to the elbow, whose deceleration helps the racket accelerate
more. On forehands the elbows passes the torch to the wrist, but not on backhands.
MORE ACCELERATION
All in all the arm's parts compress into the body (to reduce their moments of inertia to increase
the stroke's angular momentum) in an effort to whip the racket face around the arm and the body
as fast as possible to hit the ball head-on. In a not so small way, this is similar to an ice skater
spinning in a circle with her arms extended who then brings them in to spin faster. Of course we
don't spin around, but for the small moment of a forward swing, the arms come in closer to the
body to increase our racket's forward acceleration.
6F, left photo, shows the arm extended with the racket back. 6F top photo shows the arm coming
in closer to the body during the forward swing for leverage dynamics, what you want. 6F bottom
shows what to avoid, the arm extending away from your body laterally during the forward swing.
6G shows the arm folded, then unfolded during the swing for backhands in order to maintain
leverage dynamics, you don't want to swing the arm straight out away from you. It's the same for
two handed backhands, even though there are styles where the arms straighten and the wrists (not
the elbows) act as the pivot points.
WHAT ABOUT THE PROS?
Photo 6H, left, shows the arm placement a pro often uses when
taking the racket back on the forehand. The elbow is up high, the
arm is drawn back in exaggerated form, the body's coiling, the
stance is open. But they, too, from this position, must adhere to the
arm's leverage dynamics. If they don't, and a lot of them don't, their
forehands aren't what they want them to be. The exaggerated use
of the arm during a pro's swing is a symptom of inefficiency, much
like low gas mileage for a large automobile engine.
The 6H photo on the right shows adherence to the arm's leverage
dynamic: the elbow drops and the arm comes in closer to the body for leverage and speed, and
will resemble 6F top photo right during the forward swing. Though some pros extend laterally on
� Mark Papas Step 6 p.5 /7
their forehands, it's definitely more the exception than the rule. On forehands you have to get
closer to the ball than you're used to because stretching, or extending, equals leverage loss. And
on backhands you have to resist straightening the arm as part of the stroke's objective because
that, too, equals leverage loss.
A SIMPLE TENNIS QUIZ
Now for my simple tennis quiz. What hits the ball? Quickly, answer. It's not the racket, it's the
racket's face, or strings. Keep this in mind.
What part of your body swings the racket? Answers have been shoulder, arm, chest, body. Well,
the racket is not connected to any of those points. The shoulder doesn't swing the racket any
more than the arm. The hand does.
Your hand, then, swings what to hit the ball? The racket? No, that doesn't hit the ball. The hand
swings... the strings. Okay, end of quiz.
Many popular stroking ideas inhibit acceleration, such as extending the arm out away from your
body, straightening the arm for the contact, reaching out to the side, swinging from the shoulder.
My favorite is swinging the arm to swing the racket, which is the cart pushing the horse.
The arm is bent at contact, never straight, even on backhands. It straightens momentarily after
contact, like it does the moment after your throw a ball. The arm doesn't straighten for an
effective swing any more than it straightens to throw a ball. On backhands the arm is folded
across the stomach, unfolds during the swing, and is bent after contact.
The hand flexes at the wrist on forehands. There's a natural spring to the wrist on a forehand, a
bit of a throwing motion, and it becomes the last common point after the elbow to help accelerate
the racket head into the ball. The wrist is to be used, not abused, it doesn't flop or break as on
serves and overheads. Wristy is the wrong way to describe using the natural spring the wrist
provides, and without it the forehand doesn't mature.
A popular idea it to keep the wrist stiff on a forehand to commit fewer errors. While there is
literal truth to that reasoning, this kind of forehand isn't a weapon and leads to arm or shoulder
injury since you're denying the natural spring of the wrist.
Part II follows in Step 7
� Mark Papas Step 6 p.6 /7
OLD THINK NEW THINK
To Hit Through The Middle Of The Ball
� swing straight to the net � swing INTO the ball's flight line
� racket face parallel to net � racket face at a right angle to ball's flight line
Racket Acceleration
� large backswing � large backswing is not needed
� shoulder swings the racket � hands swings the racket
� swing away from the body � arm gets closer to the body
� swing to the net � swing head-on into the ball
� hit the ball hard � focus beyond the ball
� long strokes accelerate more � acceleration is a burst of speed, not length
� the body's larger muscle groups rotate � 2 directions for 1 contact
to accelerate the swing more
� Mark Papas Step 6 p.7 /7