biomechanics for advanced tennis

gzhpcu

Professional
Just read a great book: Biomechanics of Advanced Tennis, edited by Bruce Elliott, Machar Reid and Miguel Crespo.

How to achieve high racket speed?

The biomechanical elements:

  • elastic energy: muscle stretch-shorten cycle (for example: on forehand - supination of forearm prior to hitting in order to accelerate pronation on impact)
  • counterforce (pushing against ground with legs for serve, smash, groundstrokes)
  • inertia (resistance to movement): linear and radial (on one-handed backhand, keep your elbow bent and close to body at start of forwardswing to increase speed)
  • momentum: linear - step into ball, angular - rotate into ball
  • balance
You can apply this for the serve and groundstrokes. The more of these elements you incorporate, the more racket speed you achieve.
 
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subaru3169

Semi-Pro
a couple of these points, i've tried telling a couple ppl in my tennis club.. but of course, they never listen to me since i'm like half their age=/
 

Ninjamike

New User
Cool, I just had a small segment of Biomechanics at the University where i study.
What you are writing is very interesting. Im just thinking, didnt this book mention anything on pressure on the joints? The force should increase significantly on the joints by increasing the preassure on the joints, did the book mention any numbers?
Also, would you like to explain the first point to me a little more closly =)
I just play tennis for fun with friends and would like to understand that point better.
(sorry if this post got wierd, english not first language)
 

gzhpcu

Professional
Also, would you like to explain the first point to me a little more closly =)
I just play tennis for fun with friends and would like to understand that point better.
(sorry if this post got wierd, english not first language)
When you stretch a muscle, you get a rubber band effect on releasing it.

On the example I cited, for the windshield wiper movement on a topspin forehand, you want to pronate (rotate counter clockwise) your forearm. If you supinate (rotate clockwise) prior to hit, you can then accentuate the pronation. Watch Federer do this...
 
When you stretch a muscle, you get a rubber band effect on releasing it.

On the example I cited, for the windshield wiper movement on a topspin forehand, you want to pronate (rotate counter clockwise) your forearm. If you supinate (rotate clockwise) prior to hit, you can then accentuate the pronation. Watch Federer do this...

That's a good note. Everyone talks about pronation, but if you supinate on prep you get more pronation; essentially you can't have pronation without prior supination.
 
C

chico9166

Guest
Try this. Move to the top of the backswing before the raquet drop. Close the face of the racquet and make sure the elbow is "kicked out' a little.

Lower the hitting structure from there. (face down, Pat the Dog)

At teh bottom of the backswing, rotate the butt cap of the racquet towards the right net post. This in effect is supination. If you do this properly, you'll notice a couple of things.

1.The elbow will "move in" to the rib cage.

2.The elbow will also be in front of, or lead the racquet head which has been rotated backwards, and down. This is the "slot' position.

3.Depending on grip structure, the forearm will be turned up slightly. (The stronger the grip, the more pronounced this is, generally speaking ,and thus more available hand and arm rotation.

Although most people don't realise it, supination occurs to a greater or lesser extent in all loop forehands. I think that the duration between the stretch and reflex is key. The shorter the time period the more balistic the response.

So in many big forehands, the arm is not supinated until the core initiates its foreward rotation.
 
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Just read a great book: Biomechanics of Advanced Tennis, edited by Bruce Elliott, Machar Reid and Miguel Crespo.

How to achieve high racket speed?

The biomechanical elements:

  • elastic energy: muscle stretch-shorten cycle (for example: on forehand - supination of forearm prior to hitting in order to accelerate pronation on impact)
    You can apply this for the serve and groundstrokes. The more of these elements you incorporate, the more racket speed you achieve.


  • To get the benefits of the elastic energy the muscle has to be stretched for just the split second before firing for a stroke. This is the principal reason behind the recommendation of adding in that little extra takeback and body rotation just before your forward swing. Preparing too early with your arm/torso/legs in a maximal backswing pose will result in your muscles expending energy, resulting in not being abel to generate as much energy when you actually swing forward.
 
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Blake0

Hall of Fame
To get the benefits of the elastic energy the muscle has to be stretched for just the split second before firing for a stroke. This is the principal reason behind the recommendation of adding in that little extra takeback and body rotation just before your forward swing. Preparing too early with your arm/torso/legs in a maximal backswing pose will result in your muscles expending energy, resulting in not being abel to generate as much energy when you actually swing forward.

So exactly how and which muscle do you stretch the split second before firing?
Do you mean when you supinate and the buttcap is pointing toward the ball?
 
So exactly how and which muscle do you stretch the split second before firing?
Do you mean when you supinate and the buttcap is pointing toward the ball?

While you want to prepare early for the ball, you don't want to stand there with trunk, legs and arm maximally rotated or drawn back for an extended period. Just before the ball arrives is when to rotate the trunk around on the legs to load more for the shot. I think just about everyone develops this timing, but some can go through a phase when learning a stroke where they believe they will get more power if they wind up maximally well before the ball arrives.
http://www.usta.com/USTA/Global/Pla...e/all/114390_Technique_The_Kinetic_Chain.aspx
http://tt.tennis-warehouse.com/showthread.php?t=260045
http://www.itftennis.com/shared/medialibrary/pdf/original/IO_24964_original.PDF
 
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So exactly how and which muscle do you stretch the split second before firing?
Do you mean when you supinate and the buttcap is pointing toward the ball?

While you want to prepare early for the ball, you don't want to stand there with trunk, legs and arm maximally rotated or drawn back for an extended period. Just before the ball arrives is when to rotate the trunk around on the legs to load more for the shot. I think just about everyone develops this timing, but some can go through a phase when learning a stroke where they believe they will get more power if they wind up maximally well before the ball arrives.
 

J011yroger

Talk Tennis Guru
Try this. Move to the top of the backswing before the raquet drop. Close the face of the racquet and make sure the elbow is "kicked out' a little.

Lower the hitting structure from there. (face down, Pat the Dog)

At teh bottom of the backswing, rotate the butt cap of the racquet towards the right net post. This in effect is supination. If you do this properly, you'll notice a couple of things.

1.The elbow will "move in" to the rib cage.

2.The elbow will also be in front of, or lead the racquet head which has been rotated backwards, and down. This is the "slot' position.

3.Depending on grip structure, the forearm will be turned up slightly. (The stronger the grip, the more pronounced this is, generally speaking ,and thus more available hand and arm rotation.

Although most people don't realise it, supination occurs to a greater or lesser extent in all loop forehands. I think that the duration between the stretch and reflex is key. The shorter the time period the more balistic the response.

So in many big forehands, the arm is not supinated until the core initiates its foreward rotation.

Hey man, I tried to send you an e-mail and it was returned. Did you change your address?

J
 

plasma

Banned
counterforce on groundstrokes is timing as well as deep knee bend. Also relaxation as kinetic energy and elastic force and not brute muscular force is used. Ideally the weight of the racquet achieves momentum with the least amount of muscular force needed.
 

Majik

Rookie
What I'm seeing is a slight jump to load the leg when they land before they push off to rotate the trunk (like a split step).

There is also putting your arm out parallel to the net, rotating it in the direction of the net to help guide your racquet arm, and then pulling in your guiding arm as you make contact with the ball. Does this help create a back stop in the should so that the racquet arm acts more like a whip?

The question I have is how high does the ball have to be before you can unload on it? And how do you get topspin on lower balls? Do you simply swing up more with less forward motion of the racquet?
 

Majik

Rookie
Right. If you delay 1 second between stretch and shorten, you lose 50% of the energy, 2 seconds -75%.

Is there such a thing as too little time between stretch and contract before you start pulling muscles and ripping tendons?
 

mrcalon

Rookie
^^ only if there's a major discrepancy in strength between the two muscles. For example, most rotator cuff injuries happen because the external rotators are weak in most people relative to internal rotators. The book gzh refers to has a suggested strength ratio..i cant remember it off hand.
 

gzhpcu

Professional
^^ only if there's a major discrepancy in strength between the two muscles. For example, most rotator cuff injuries happen because the external rotators are weak in most people relative to internal rotators. The book gzh refers to has a suggested strength ratio..i cant remember it off hand.
If the difference in this ratio is too large (about 1.5:1) it reduces the stability of the shoulder region increasing the likelihood of injury.
 

ho

Semi-Pro
Just read a great book: Biomechanics of Advanced Tennis, edited by Bruce Elliott, Machar Reid and Miguel Crespo.

How to achieve high racket speed?

The biomechanical elements:

  • elastic energy: muscle stretch-shorten cycle (for example: on forehand - supination of forearm prior to hitting in order to accelerate pronation on impact)
    You can apply this for the serve and groundstrokes. The more of these elements you incorporate, the more racket speed you achieve.

  • Racket speed in the PULL stroke create by kinetic chain (one element after another) supination of forearm create spin and reduce forward racket speed.
    in the PUSH stroke, there no need to produce racket speed, still it produce ball speed.
    If that is what we want, then there is no need to be elastic in ground stroke.
    Either the author of the book wrongly define elastic energy or you explain it differently.
 

gzhpcu

Professional
Racket speed in the PULL stroke create by kinetic chain (one element after another) supination of forearm create spin and reduce forward racket speed.
in the PUSH stroke, there no need to produce racket speed, still it produce ball speed.
If that is what we want, then there is no need to be elastic in ground stroke.
Either the author of the book wrongly define elastic energy or you explain it differently.
What we want is a fast windshield wiper movement. This is achieved by pronation. Supination prior to supination accentuates it. We are talking about the racket speed component responsible for spin, not for speed.
 

ho

Semi-Pro
What we want is a fast windshield wiper movement.
common wisdom: to bring the ball in, need a fast windshield. Common mistake: that is not actually happen on the court. A fast windshield not just hard to do, but also erratic, it can be great today, but not sure next week.
It's the prolonge racket contact with the ball bring the ball in easier than a heavy spin.
At contact, ball will compress heavily on the string bed, the more it is compressed, the more it is easier to control, and the more speed you get when ball bounce out. A little low to high or a simple racket tilt, with the prolongation of contact, will even magnify the effect of spin better than a heavy windshield.
 

LuckyR

Legend
Just read a great book: Biomechanics of Advanced Tennis, edited by Bruce Elliott, Machar Reid and Miguel Crespo.

How to achieve high racket speed?

The biomechanical elements:

  • elastic energy: muscle stretch-shorten cycle (for example: on forehand - supination of forearm prior to hitting in order to accelerate pronation on impact)
  • counterforce (pushing against ground with legs for serve, smash, groundstrokes)
  • inertia (resistance to movement): linear and radial (on one-handed backhand, keep your elbow bent and close to body at start of forwardswing to increase speed)
  • momentum: linear - step into ball, angular - rotate into ball
  • balance
You can apply this for the serve and groundstrokes. The more of these elements you incorporate, the more racket speed you achieve.


Seems like a Biomechanics guy who knows squat about tennis, hooked up with 2 tennis "psychologists". Could be good, could be worthless, tough to say.
 

gzhpcu

Professional
Seems like a Biomechanics guy who knows squat about tennis, hooked up with 2 tennis "psychologists". Could be good, could be worthless, tough to say.
Elliott is an Australian state level tennis coach, and knows plenty about tennis.
 

user92626

G.O.A.T.
Just read a great book: Biomechanics of Advanced Tennis, edited by Bruce Elliott, Machar Reid and Miguel Crespo.

How to achieve high racket speed?

The biomechanical elements:

  • elastic energy: muscle stretch-shorten cycle (for example: on forehand - supination of forearm prior to hitting in order to accelerate pronation on impact)
  • counterforce (pushing against ground with legs for serve, smash, groundstrokes)
  • inertia (resistance to movement): linear and radial (on one-handed backhand, keep your elbow bent and close to body at start of forwardswing to increase speed)
  • momentum: linear - step into ball, angular - rotate into ball
  • balance
You can apply this for the serve and groundstrokes. The more of these elements you incorporate, the more racket speed you achieve.

Hmm... i can hit the crap out of the ball just fine, as can most people I play with. No problem there.

The problem is understanding and performing the physics of hitting the ball that makes it clear the net sufficiently, spin and remain pacey and land inbound. Hardly about strength
 

ho

Semi-Pro
The problem is understanding and performing the physics of hitting the ball that makes it clear the net sufficiently, spin and remain pacey and land inbound. Hardly about strength
very true, but it will not be a problem if you stick around here and ask questions.
unlike most of old timer tennis coach teach: "bend your knee, hit from low to high 30 degree, feel the strain in your body..." and so on...all start at understanding the physic law of collision of two SOFT OBJECT. which something that even at college level don't teach. (they teach only collision of two RIGID OBJECT).
 
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user92626

G.O.A.T.
all start at understanding the physic law of collision of two SOFT OBJECT. .


So, can you explain that in detail for us. I'm afraid that too many people already know how to put tremendous power in hitting but very few manage to keep the ball in at the same time.
 

ho

Semi-Pro
So, can you explain that in detail for us. I'm afraid that too many people already know how to put tremendous power in hitting but very few manage to keep the ball in at the same time.
i did explain in several post.
basicly, from the law of impact of 2 soft object, time of contact is a critical ingredient of power and control. easely explain it, the more your string bed hold the ball (the ball deformed on the string bed) the more you got power and control.
Drop a ball on the concrete floor then drop a ball on the soil, you will see how much different it bounce up, in term of control and power.
Now i let you figure out by yourseft, with your own style, what to do to get the best out of your ability.
that's the way to learn tennis. you understand the concept first, then technique and tips latter.
 

ho

Semi-Pro
Anyone notice the more supination there is, the stronger the shot?
hard to say, the more you supinate, the more extra muscle you put into the shot. it also the more you brush up the ball. ball do not fully compress as when you hit flat. the result ?
hard to say.
 

gzhpcu

Professional
hard to say, the more you supinate, the more extra muscle you put into the shot. it also the more you brush up the ball. ball do not fully compress as when you hit flat. the result ?
hard to say.
If you only hit flat the ball has a very small margin of error. That is why the pros practically all hit with a lot of topspin. A heavy ball combines speed with spin. You hit well through the ball but also upwards. The upwards motion is accentuated by the windshield wiper motion. This is characteristic of modern tennis with light rackets.
 

ho

Semi-Pro
A heavy ball combines speed with spin. You hit well through the ball but also upwards.
this basicly how advance player hit the ball: "HIT WELL THRU" the ball with a little upward, windshield and tilt racket face combine.
with a lot of topsin ? it a depend on your definition of a lot. If i was you, i hit with very little topspin as possible: it conserve ennegy and conserve consistancy. A lot of topspin shorten and slow the ball, sit it up , pretty much what your man across the net want.
Light racket? As your game improve, you want to use heavier racket as any body else.
 

gzhpcu

Professional
this basicly how advance player hit the ball: "HIT WELL THRU" the ball with a little upward, windshield and tilt racket face combine.
with a lot of topsin ? it a depend on your definition of a lot. If i was you, i hit with very little topspin as possible: it conserve ennegy and conserve consistancy. A lot of topspin shorten and slow the ball, sit it up , pretty much what your man across the net want.
Light racket? As your game improve, you want to use heavier racket as any body else.
I am talking about a really fast swing. Plenty of extension and windshield wiper motion. It will not slow down the ball much, and extension will ensure that the ball is long. The ball sits up and is short if after impact the swingpath goes up too soon, not if the extension is long and in front.
The trend in the past years has been stiffer and lighter rackets.
 

5263

G.O.A.T.
I am talking about a really fast swing. Plenty of extension and windshield wiper motion. It will not slow down the ball much, and extension will ensure that the ball is long. The ball sits up and is short if after impact the swingpath goes up too soon, not if the extension is long and in front.
The trend in the past years has been stiffer and lighter rackets.

stiffer strings too.
 

ho

Semi-Pro
stiffer strings too.
very true but it may have to go beyond that.
Fibak comment on Lendle forehand: Lendle generate big power by at the point of contact, squeeze his hand. (Tennis Magazine)
that something most of people cannot do, including me some 25 years ago.
As you see, the different betwwen concrete and soil is the concrete is stiff, soil are not. There come the concept of PUSH stroke: everything behind the string bed have to be stiff. racket stiff, string stiff. Body and and arm as an unit stiff. There is no elasticity in this concept.
How do we make our body and arm stiff: at first it have to be ONE UNIT. then make them stiff by taking a deep breath and hold your breath. In Kung fu, it's called inner energy.
By the way, by coincidence, the word PUSH here make some naive tennis coach think is to use your hand to PUSH the ball. that leave them make a fool out of himseft in public.
 
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