A Study on the Mechanics of the Forehand

Limpinhitter

G.O.A.T.
Below is a link to an article (and some quotes from the article), on a study from 2010 comparing the mechanics of the forehands of: (1) 6 ATP professionals, and (2) 7 high performance youth players, that I posted a link to several years ago. Based on some of the recent discussion in this section I thought it would be interesting and helpful to post it again.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761808/

"Key points
  • Different timing of maximum angular pelvis and trunk rotations separated the elite from the high performance players.
  • The elite group tended to reach higher horizontal shoulder and racquet velocities than the high performance group.
  • In addition to maximum angular velocities, maximum racquet, shoulder, and hip alignment angles were similar between groups.
  • To improve the forehand performance level of their athletes, coaches should focus on proper pelvis and trunk rotation."
"Practical implications
Our findings suggest that for the improvement of the forehand performance level, coaches and athletes should focus mainly on three things: proper 1) pelvis and 2) trunk rotation velocity and 3) their timing. A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. In case of vigorous trunk angular velocity, the players will even step forward with their rear leg after impact. Overall this can be a model for technique training in the tennis forehand."
 

Tennisanity

Legend
Interesting, so coaches should focus on trunk ROTATION, and not just saying meaningless things like do the fundamentals whilst bilking unsuspecting people out of hard earned money. Interesting.
 

Limpinhitter

G.O.A.T.
Interesting, so coaches should focus on trunk ROTATION, and not just saying meaningless things like do the fundamentals whilst bilking unsuspecting people out of hard earned money. Interesting.
I'm not sure if the person that you are referring to coaches for a living, or just coaches his daughter. What is clear is that he's not a fan of the fundamentals of the modern forehand.
 

Fxanimator1

Hall of Fame
A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. In case of vigorous trunk angular velocity, the players will even step forward with their rear leg after impact. Overall this can be a model for technique training in the tennis forehand."

The bolded part is what I was referring to in the @Raul_SJ thread about "hip rotation..."
 

Limpinhitter

G.O.A.T.
The bolded part is what I was referring to in the @Raul_SJ thread about "hip rotation..."
In my view, that's true, but, it's not something you should have to think about. If you think about initiating the forward swing by rotating the hip, the leg drive will be automatic, and so will the remainder of the kinetic chain, and the "flip," if you maintain a loose, relaxed arm and grip. The "umph" is in the legs and the abdominal muscles.
 

Bender

G.O.A.T.
I'm not sure if the person that you are referring to coaches for a living, or just coaches his daughter. What is clear is that he's not a fan of the fundamentals of the modern forehand.
Perhaps I'm missing something, but isn't trunk rotation / leg drive / hip rotation all fundamentals of the forehand?
 
Interesting to see that coordinative timing is a more significant measure of elite/expert performance differences than absolute segment velocities.

Why did they ask participants to change direction with the ball?
 
Actually most coaches teach Rotation of the upper Body but the Focus on the coil (unit turn) rather than the uncoil. most Amateur Players don't lack the ability to uncoil but they don't coil in the first place.

If you have a good shoulder turn in the takeback usually the uncoil will take care of itself.
 
Actually most coaches teach Rotation of the upper Body but the Focus on the coil (unit turn) rather than the uncoil. most Amateur Players don't lack the ability to uncoil but they don't coil in the first place.

If you have a good shoulder turn in the takeback usually the uncoil will take care of itself.
Doesn't this research suggest that it's the timing of the segments related to uncoiling that separates elite and high performance? How do most coaches facilitate this?
 

Limpinhitter

G.O.A.T.
Doesn't this research suggest that it's the timing of the segments related to uncoiling that separates elite and high performance? How do most coaches facilitate this?
I think that's the primary distinction cited in this study between the two levels of play. I'd be surprised if many, or any, coaches know this much less facilitate it.

But, from my view, the most obvious and significant distinction between the various levels of play, be it top 10 ATP from top 50, top 50 from top 200, ATP from high level amateur, etc., etc., is the quality and consistency of shot preparation and set up. The role that shot preparation plays in the timing of uncoiling is not discussed, but, I think that there is probably a connection.
 
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I think that's the primary distinction cited in this study between the two levels of play. I'd be surprised if many, or any, coaches know this much less facilitate it.

But, from my view, the most obvious and significant distinction between the various levels of play, be it top 10 ATP from top 50, top 50 from top 200, ATP from high level amateur, etc., etc., is the quality and consistency of shot preparation and set up. The role that shot preparation plays in the timing of uncoiling is not discussed, but, I think that there is probably a connection.
Ive seen our head coach focus on the speed of the hips and bringing the drive hip/leg through but not the timing of that. I skimmed the paper but I don't recall whether there was any pre-shot movement that could affect preparation, nice idea for a paper. Good paper and some nice ideas to get wise to.
 

Curious

Legend
If you have a good shoulder turn in the takeback usually the uncoil will take care of itself
I think it's crucial to emphasize that a unit/shoulder turn or a coil is no good unless you do it with an open stance. With a closed stance it's more forced/muscled sort of movement whereas with the open stance it's like a spring or rubber band snapping back.
 

Limpinhitter

G.O.A.T.
I think it's crucial to emphasize that a unit/shoulder turn or a coil is no good unless you do it with an open stance. With a closed stance it's more forced/muscled sort of movement whereas with the open stance it's like a spring or rubber band snapping back.
I think it would be more accurate to say that a neutral or closed stance limits the execution of the kinetic chain. It can still be done to a limited degree in a neutral or closed stance.
 

Limpinhitter

G.O.A.T.
Oh good, another study of the mechanics of the tennis forehand. This will help millions of people play like Federer. Forget that most players can barely hit the ball, we're going to discuss the minut differences between great players and super great players and incorporate them into our game. This should be very productive.

Why doesn't anyone talk about core ankle rotation? It's pivotal (no pun intended) that we understand the ankles roll in the modern forehand if we hope to hit the ball like Del Potro.
More timeless words of wisdom from our resident charter member of the Flat Earth Society. We would all be lost without the benefit of your snark and sarcasm.
 

Curiosity

Professional
The effect of separation angle on the ability to hit a faster forehand does not depend on stance. The action necessary to achieve the same separation angle if using a semi-open or neutral stance varies from the action (extent of rotation back) in the open stance, of course, as we have to turn our shoulders farther around (relative to the net) if we're going to get a certain degree of SA. Humorously true, given Donneybrook's sarcastic ankle comments. It is necessary to consider, if only intuitively, the orientation of the feet and the degree of knee flex, not merely the stance, when determining at what point the hips will stop rotating back with the shoulders, allowing separation to increase.

The NIH article linked by the OP contains a variety of confusions. One such is this: The authors (all native German speakers) use the term "internal shoulder rotation" to mean different things at different times. Through most of the paper they use it as a synonym for "rotation of the shoulder relative to the long axis of the body," i.e. the spine. Later in the paper they quote ITF sources, Crespo et al, and use the term as the ITF publications do, in which ISR refers to the rotation of the upper arm in the shoulder socket. Therefore when the authors quote the ITF (Reid/Crespo and others) figure, that up to 40% of the power of the forehand depends on ISR...they are not referring to the "rotation of the shoulders" which they actually measured in their study. The extent, speed, and timing of both ISR and UB rotation are keys to hitting a high speed forehand, as you know.

It seems to me the purpose and physical measures of the study were somewhat useful in confirming the importance of separation angle and high torso rotation speed. It also seems to me that the writing itself is at times ambiguous and confusing.

The principal finding of the paper seems to be this: Both the ATP pros and top juniors achieved similar rotation extent and speed (taking roughly .33 seconds to get from first forward racquet motion through to contact), but the pros timed their start better. In other words with greater training, consequent increase in physical strength, and experience .....timing improves. Not surprising. The top pros have fabulously precise timing.

I basically agree with Raul, SJ's comments and point of view.
 

Limpinhitter

G.O.A.T.
I use mostly neutral stance. And I do notice any limitation.

See also the ITF study http://en.coaching.itftennis.com/media/114014/114014.pdf

This graph doesn't mean anything to me. What the title doesn't state is whether there is a difference in average racquet velocity between open, neutral and closed stances. There is also this chart later in your link which may imply an answer to that question.

Open or Square Stance?
Forehand Preparation
80% Open stance
20% Semi Open
88% of players DO NOT step into the ball
≈ 6% Step In
≈ 6% Step Back
No difference between male and female
220 Male and 130 Female Top Players: 4 Clay Court Tournaments

PS: For some reason the page did not copy and paste for me the way yours did.
 
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Curiosity

Professional
I find the ITF publication, ITF Coaches Education Programme, Coaching High-Performance Players Course, The Forehand, by Reid and Crespo, quite clear. I think taking the detour into the NIH sport research paper from Salzburg University is a waste of time....since it is less clear and the underlying data is unavailable to us. Did I mention it also lacks good illustrations? laugh.
 

Raul_SJ

Legend
This graph doesn't mean anything to me. What the title doesn't state is whether there is a difference in average racquet velocity between open, neutral and closed stances.
Coaches advise against the closed stance so I am not sure why the closed stance is of interest...

From Indiana University Study: "The data did not support the hypothesis of a greater trunk angular velocity in open stance compared to square stance forehands."

Trunk and racket kinematics at impact in the open and square stance tennis forehand
Article in Biology of Sport · January 1999
Rafael E Bahamonde Indiana University-Purdue University Indianapolis



 
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TennisCJC

Legend
Actually most coaches teach Rotation of the upper Body but the Focus on the coil (unit turn) rather than the uncoil. most Amateur Players don't lack the ability to uncoil but they don't coil in the first place.

If you have a good shoulder turn in the takeback usually the uncoil will take care of itself.
I am not a coach but did coach my kids and wife. They all responded well to the concept of coil and uncoil. My daughter and wife are small in statue but my wife did learn to coil and uncoil into a FH and hit it quite effectively. I would teach my daughter this on her 2HBH and she was able to hit good deep 2HBHs with decent topspin and pace. They both responded to the concepts very well. I think all tennis players should be taught these concepts and vast majority can work it into their games. Yes, they wont all end up looking like pros but the basic concept of using the leg, hips and shoulders to drive the stroke can be worked into an adult's game.
 

Limpinhitter

G.O.A.T.
I am not a coach but did coach my kids and wife. They all responded well to the concept of coil and uncoil. My daughter and wife are small in statue but my wife did learn to coil and uncoil into a FH and hit it quite effectively. I would teach my daughter this on her 2HBH and she was able to hit good deep 2HBHs with decent topspin and pace. They both responded to the concepts very well. I think all tennis players should be taught these concepts and vast majority can work it into their games. Yes, they wont all end up looking like pros but the basic concept of using the leg, hips and shoulders to drive the stroke can be worked into an adult's game.
Agreed! And it's easier to learn if they don't have to unlearn technqiue suited to 14+ oz., 65 sq. in., wood racquets with sweet spots the size of a tennis ball. :D
 
D

Deleted member 23235

Guest
No. None of them are fundamentals of a forehand. The fundamentals of a forehand are unit turn backswing forward swing to contact and follow through. These make up the basic Foundation of a forehand. Everything else is basically a byproduct of doing the fundamentals correctly.
From an engineering standpoint, I find it interesting to break down a stroke into individual contributors of the stroke (ie. which parts of the body do what, what order etc...)

From a teaching standpoint, i agree, just saying/showing a unit turn, is usually more than enough for a student to properly mimic the fundamentals (load back leg, drive off back leg, start hip rotation, blah, blah, blah).

Breaking down the details (to a student), is kinda like describing to someone how to walk... contract hamstrings, pick up foot, lean at ankle, let gravity do it's thing, catch yourself with foot you just picked up, pick up rear foot, etc... sounds ridiculous and confusing to teach someone (beginner) this way.
 

Limpinhitter

G.O.A.T.
Coaches advise against the closed stance so I am not sure why the closed stance is of interest...

From Indiana University Study: "The data did not support the hypothesis of a greater trunk angular velocity in open stance compared to square stance forehands."

Trunk and racket kinematics at impact in the open and square stance tennis forehand
Article in Biology of Sport · January 1999
Rafael E Bahamonde Indiana University-Purdue University Indianapolis



This is dated 1999. In my view, it predates the complete evolution (and understanding) of the modern forehand we see today.
 

Fxanimator1

Hall of Fame
From an engineering standpoint, I find it interesting to break down a stroke into individual contributors of the stroke (ie. which parts of the body do what, what order etc...)

From a teaching standpoint, i agree, just saying/showing a unit turn, is usually more than enough for a student to properly mimic the fundamentals (load back leg, drive off back leg, start hip rotation, blah, blah, blah).

Breaking down the details (to a student), is kinda like describing to someone how to walk... contract hamstrings, pick up foot, lean at ankle, let gravity do it's thing, catch yourself with foot you just picked up, pick up rear foot, etc... sounds ridiculous and confusing to teach someone (beginner) this way.
Everyone's background plays a large role in how they learn...and teach.
I taught my son forehands in animation terms. I broke it down into several "key poses" which get linked together into one motion.
 

deco0028

Rookie
Below is a link to an article (and some quotes from the article), on a study from 2010 comparing the mechanics of the forehands of: (1) 6 ATP professionals, and (2) 7 high performance youth players, that I posted a link to several years ago. Based on some of the recent discussion in this section I thought it would be interesting and helpful to post it again.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761808/

"Key points
  • Different timing of maximum angular pelvis and trunk rotations separated the elite from the high performance players.
  • The elite group tended to reach higher horizontal shoulder and racquet velocities than the high performance group.
  • In addition to maximum angular velocities, maximum racquet, shoulder, and hip alignment angles were similar between groups.
  • To improve the forehand performance level of their athletes, coaches should focus on proper pelvis and trunk rotation."
"Practical implications
Our findings suggest that for the improvement of the forehand performance level, coaches and athletes should focus mainly on three things: proper 1) pelvis and 2) trunk rotation velocity and 3) their timing. A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. In case of vigorous trunk angular velocity, the players will even step forward with their rear leg after impact. Overall this can be a model for technique training in the tennis forehand."
Thanks, interesting reading.
I am "coaching my 2 kids" as they were not very motivated with their pro coach who failed to identify and correct some fundamental biomechanical issues until I pointed them out.
I am trying to focus on unit turn during takeback, and weight transfer from rear to front foot. When coiled, unless they are arming the ball, they have to uncoil to make the stroke.This article is basically addressing this, but in a more analysed fashion.
Thanks again.
 

RetroSpin

Hall of Fame
A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. In case of vigorous trunk angular velocity, the players will even step forward with their rear leg after impact. Overall this can be a model for technique training in the tennis forehand."
I assumed when I read this that the "separation angle" they refer to was the separation between the pelvis and shoulders. Studying slomo videos of top pro FHs however seems to indicate to me that there is virtually no such separation. They rotate their hips and upper body as a unit. So is the separation something else, perhaps arm angle relative to the body, or are they just dead wrong?

I was interested in this concept because golf instruction has foundered over the issue of hip and shoulder separation. A prominent teaching pro, Jim McLean, published a very influential article in one of the golf magazines years ago in which he claimed that the key to distance was achieving max separation at the top of the backswing. He termed it the X factor. This led to the idea that hip rotation should be restricted, which is a very unnatural way to hit a golf ball. Later, iconoclastic teacher Kelvin Miyahira proved that most big hitters do not restrict hip rotation but in fact try to maximize it. Using the X factor to power your swing forces you to rely on the oblique muscles, which are relatively small.
 

Tennisanity

Legend
I assumed when I read this that the "separation angle" they refer to was the separation between the pelvis and shoulders. Studying slomo videos of top pro FHs however seems to indicate to me that there is virtually no such separation. They rotate their hips and upper body as a unit.
Relative to what?
 

Limpinhitter

G.O.A.T.
Thanks, interesting reading.
I am "coaching my 2 kids" as they were not very motivated with their pro coach who failed to identify and correct some fundamental biomechanical issues until I pointed them out.
I am trying to focus on unit turn during takeback, and weight transfer from rear to front foot. When coiled, unless they are arming the ball, they have to uncoil to make the stroke.This article is basically addressing this, but in a more analysed fashion.
Thanks again.
The modern forehand is based on rotational (angular), momentum as opposed to the traditional forehand which utilizes linear momentum (weight transfer and swing from back to front). With modern technique, weight transfer in the traditional sense is not an essential part of it. Although, you will see players transferring their weight from side to side (typically about 4 O'Clock to 10 O'Clock as opposed to 6 to 12 on a traditional forehand), as they rotate from an open stance, pros and good players often finish forehands with their weight on the right foot (assuming they are righties), and their left foot off of the ground, no weight transfer at all, and still generate tremendous racquet head speed because they are utilizing rotation, not weight transfer.

In addition, there is another key part of the equation when executing a modern forehand - arm rotation as if you are opening and closing a door knob. That rotation, which Rick Macci calls "the flip," combined with upper body rotation is how the pros create so much racquet head speed, power and spin. The key is that, in order to execute arm rotation effectively, the arm and racquet have to be in the correct position at the back of the backswing, and the backswing has to be short ie: the hand no further back than about 5:00, and the top of the racquet pointing to the right side fence, not the back fence and certainly not the left side fence as many WTA players do. If the hand or racquet are too far back, then the swing will be disconnected from upper body rotation, and you will squander the flip and merely drag the racquet through contact the way most WTA players do.

Study these pictures of Federer carefully. Notice the position of his feet upper body arm and racquet in the set up position at the back of his backswing. Notice the short backswing and the direction that his racquet is pointing to. That is ideal, in my view. Notice how he initiates his forward swing with hip rotation which which pulls his torso, which pulls his shoulders, which pulls his arm and racquet and causes the racquet head to - then (after the forward swing has started) - rotate back, "the flip." Also notice that what little weight transfer there is, is from side to side.



Below, the first video describes the correct arm and racquet position in the set up position at the back of the backswing (with a semi Western grip). The second video describes how the flip is executed, although it doesn't use that term.


 

RetroSpin

Hall of Fame
Notice the short backswing and the direction that his racquet is pointing to. That is ideal, in my view. Notice how he initiates his forward swing with hip rotation which which pulls his torso, which pulls his shoulders, which pulls his arm and racquet and causes the racquet head to - then (after the forward swing has started) - rotate back, "the flip."
His racquet faces the side fence because he uses more of an eastern grip. Players who use more of a western grip will face the back fence, with the exact same arm and body position.

I do not see the hip-torso-shoulder sequence in the Fed pics. From pic 1 to pic2, his hips have barely rotated at all but his shoulders clearly have. You can see this by comparing the relative positions of the strips on his shorts and his shirt. He has extended his right knee and hip somewhat.

I realize this kinetic sequencing is a basic tenet of biomechanical researchers, etc. It just doesn't seem to take place much in the real world of top pro tennis.
 

Limpinhitter

G.O.A.T.
His racquet faces the side fence because he uses more of an eastern grip. Players who use more of a western grip will face the back fence, with the exact same arm and body position.

I do not see the hip-torso-shoulder sequence in the Fed pics. From pic 1 to pic2, his hips have barely rotated at all but his shoulders clearly have. You can see this by comparing the relative positions of the strips on his shorts and his shirt. He has extended his right knee and hip somewhat.

I realize this kinetic sequencing is a basic tenet of biomechanical researchers, etc. It just doesn't seem to take place much in the real world of top pro tennis.
I said "the top of the racquet" should point to the right side fence, not the face of the racquet. You're not the first one to misunderstand what I'm trying to say.

I can clearly see Fed's hips start to rotate comparing pic #1 and #2. It definitely takes place, but, it may be a smaller movement than you were expecting.
 

Limpinhitter

G.O.A.T.
I assumed when I read this that the "separation angle" they refer to was the separation between the pelvis and shoulders. Studying slomo videos of top pro FHs however seems to indicate to me that there is virtually no such separation. They rotate their hips and upper body as a unit. So is the separation something else, perhaps arm angle relative to the body, or are they just dead wrong?

I was interested in this concept because golf instruction has foundered over the issue of hip and shoulder separation. A prominent teaching pro, Jim McLean, published a very influential article in one of the golf magazines years ago in which he claimed that the key to distance was achieving max separation at the top of the backswing. He termed it the X factor. This led to the idea that hip rotation should be restricted, which is a very unnatural way to hit a golf ball. Later, iconoclastic teacher Kelvin Miyahira proved that most big hitters do not restrict hip rotation but in fact try to maximize it. Using the X factor to power your swing forces you to rely on the oblique muscles, which are relatively small.
Funny, my understanding of the golf swing is that the hip slides toward the target before it rotates. This assures that the bottom of the swing and contact with the ground is in front of the ball, after contact.
 

deco0028

Rookie
Was the coach's name Don any chance? :)
No.Not Don.
I am relatively new to the game as a player(4.5 years), but have been exposed through my 4 children for a good number of years, and am a keen observer of tennis. Helps to have a strong understanding of anatomy and biomechanics. it is similar to soccer, martial arts,etc where a stable base and core rotation are crucial. At least for now, they look forward to hitting balls and drills for 2 hours each Sunday. One of their friends is also cycling to the courts to join in(thanks to my 10 year old daughter), so I now have three on the court. I will be the first to admit I am not a trained tennis coach, but my kids train in a weekly squad that they just commenced , and the coach there remarked on how well they hit, with good topspin. So I can't be that bad....
I just enjoy the time I spend with them, and I love being out on a court, so it's all good.
Cheers
 

deco0028

Rookie
The modern forehand is based on rotational (angular), momentum as opposed to the traditional forehand which utilizes linear momentum (weight transfer and swing from back to front). With modern technique, weight transfer in the traditional sense is not an essential part of it. Although, you will see players transferring their weight from side to side (typically about 4 O'Clock to 10 O'Clock as opposed to 6 to 12 on a traditional forehand), as they rotate from an open stance, pros and good players often finish forehands with their weight on the right foot (assuming they are righties), and their left foot off of the ground, no weight transfer at all, and still generate tremendous racquet head speed because they are utilizing rotation, not weight transfer.

In addition, there is another key part of the equation when executing a modern forehand - arm rotation as if you are opening and closing a door knob. That rotation, which Rick Macci calls "the flip," combined with upper body rotation is how the pros create so much racquet head speed, power and spin. The key is that, in order to execute arm rotation effectively, the arm and racquet have to be in the correct position at the back of the backswing, and the backswing has to be short ie: the hand no further back than about 5:00, and the top of the racquet pointing to the right side fence, not the back fence and certainly not the left side fence as many WTA players do. If the hand or racquet are too far back, then the swing will be disconnected from upper body rotation, and you will squander the flip and merely drag the racquet through contact the way most WTA players do.

Study these pictures of Federer carefully. Notice the position of his feet upper body arm and racquet in the set up position at the back of his backswing. Notice the short backswing and the direction that his racquet is pointing to. That is ideal, in my view. Notice how he initiates his forward swing with hip rotation which which pulls his torso, which pulls his shoulders, which pulls his arm and racquet and causes the racquet head to - then (after the forward swing has started) - rotate back, "the flip." Also notice that what little weight transfer there is, is from side to side.



Below, the first video describes the correct arm and racquet position in the set up position at the back of the backswing (with a semi Western grip). The second video describes how the flip is executed, although it doesn't use that term.


Thanks. The weight transfer I was referring to was from the trailing foot, to the leading foot. But they do mostly hit with a somewhat open stance. I do start with a closed stance at the start of our session to ensure they are transferring their weight appropriately.
Thanks for the photos.
 

RetroSpin

Hall of Fame
I can clearly see Fed's hips start to rotate comparing pic #1 and #2. It definitely takes place, but, it may be a smaller movement than you were expecting.
The claim was that hip rotation drives torso rotation. That is clearly not happening. The left shoulder has rotated far more than the hips. The hips and torso rotate together.
 

RetroSpin

Hall of Fame
Funny, my understanding of the golf swing is that the hip slides toward the target before it rotates. This assures that the bottom of the swing and contact with the ground is in front of the ball, after contact.
I think there are variations here between players. Some advocate a small lateral move off the ball in the backswing and a small slide forward in the downswing. Others prefer that the left hip immediately rotate away from the target line on the downswing.

Players who have to slide to prevent hitting the ball fat are generally flipping their wrists at the bottom. Trying to coordinate a slide with a flip is very difficult, which is why you don't see many Tour players doing that.
 

Limpinhitter

G.O.A.T.
The claim was that hip rotation drives torso rotation. That is clearly not happening. The left shoulder has rotated far more than the hips. The hips and torso rotate together.
No, they don't. The hip rotates first, which pulls the torso, which pulls the shoulders, which pulls the arm and racquet, in that sequence of events. That sequence, along with arm rotation (the flip), creates the lag between initiation of the forward swing with the hip and ball contact.
 

Raul_SJ

Legend
No, they don't. The hip rotates first, which pulls the torso, which pulls the shoulders, which pulls the arm and racquet, in that sequence of events. That sequence, along with arm rotation (the flip), creates the lag between initiation of the forward swing with the hip and ball contact.
Do I understand the Federer sequence corrdctly?

Pic#1 has the greatest separation angle.
When you set up, the shoulders and hips are both rotated towards the back fence, with the shoulders being more rotated.

When is the initiation of the forward swing considered to begin? Pic#1 or Pic#2?

Is Pic #2 the Macci "Pat the Dog" position and where the "flip" happens?

During that instant when the hips first lead the rotation towards the net and the shoulders lag behind (I believe Pic#2, where the "flip" and knee extension happens), are the shoulders stationary? Or do the shoulders briefly rotate towards the back fence while the hip is rotating forwards?

 
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Limpinhitter

G.O.A.T.
Do I understand the Federer sequence corrdctly?

Pic#1 has the greatest separation angle.
When you set up, the shoulders and hips are both rotated towards the back fence, with the shoulders being more rotated.

When does the initiation of the forward swing begin? Pic#1 or Pic#2?

Is Pic #2 the Macci "Pat the Dog" position?

During that instant when the hips lead the rotation towards the net (Pic#2?), are the shoulders stationary? Or do the shoulders rotate towards the back fence while the hip is rotating forwards?

Obviously, these 6 pics don't capture every point of the swing. Pic #1 is closest to the set-up position and the back of the backswing. Pic #2 shows the initiation of the forward swing with hip rotation. My understanding of the authors use of the term "separation angle" is the degree of rotation that the hips lead the torso (I think they include shoulders with torso) in the forward swing, which means that was probably at its greatest between Pic #2 and #3. In Pic #3, the shoulders have caught up to the hips and also shows the first half of the Macci "flip." I'm not sure I understand your last question. I don't think that the hips and shoulders ever rotate in opposite directions at the same time. In pic #4, the hips have stopped rotating and the shoulders have rotated past the hips. In pics #5 and #6, the momentum of shoulder rotation are now pulling the hips and back leg around.
 

Raul_SJ

Legend
I'm not sure I understand your last question. I don't think that the hips and shoulders ever rotate in opposite directions at the same time.
I thought there might be an instant, at the forward swing initiation, where the hips and shoulders rotate in opposite directions. That is the way it feels like. The hips lead forward rotation, with the racket lagging behind the wrist, the knees extending, the shoulders slightly rotating in the opposite direction before rotating in the same forward direction.

As mentioned in Post #4. "A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. "

It sounds like you are saying the shoulders do not actually rotate in opposite directions. The hips lead the forward rotation and the torso just lags behind.
 
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Limpinhitter

G.O.A.T.
I thought there might be an instant where the hips and shoulders rotate in opposite directions. That is the way it feels like. The hips lead forward rotation, with the racket lagging behind the wrist, the knees extending, the shoulders slightly rotating in the opposite direction before rotating in the same forward direction.

As mentioned in Post #4. "A good rear leg drive will initiate pelvis rotation and, consequently, increase the separation angle, which will do its part in terms of storing elastic energy for subsequent rotations. "

It sounds like you are saying the shoulders do not actually rotate in opposite directions. The hips lead the forward rotation and the torso just lags behind.
The hips initiate forward rotation from the set up position at the back of the backswing. The shoulders have fully rotated back when the hips rotate forward. If you just think about rotating the hips, the legs will do what they need to do. I don't think it's helpful to think about leg drive in this situation.

From the set up position at the back of the backswing, the forward swing is initiated by rotating the hips, which pulls the torso, which pulls the shoulders, which pulls the arm and racquet in that sequence of events.
 

Raul_SJ

Legend
No, they don't. The hip rotates first, which pulls the torso, which pulls the shoulders, which pulls the arm and racquet, in that sequence of events. That sequence, along with arm rotation (the flip), creates the lag between initiation of the forward swing with the hip and ball contact.
I'm having a bit of trouble seeing separation angles on forehands. This previous post explains it clearly for the golf swing.

To picture separation:
1) imagine a line draw between the two shoulders,
2) imagine a line drawn between the two hips.
3) imagine viewing them from above.​





Is the separation angle on the above right forehand pic 0? i.e., if the two lines are parallel there is no shoulder/hip separation?
 
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Raul_SJ

Legend
Below is a link to an article (and some quotes from the article), on a study from 2010 comparing the mechanics of the forehands of: (1) 6 ATP professionals, and (2) 7 high performance youth players, that I posted a link to several years ago. Based on some of the recent discussion in this section I thought it would be interesting and helpful to post it again.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761808/

[
The Table shows 195 degrees shoulder alignment for cross court forehand, elite player.
How is that 195 calculated. If 0 degrees is taken to be facing the net, it does not look like
players have rotated that far.





 
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D

Deleted member 23235

Guest
The hips initiate forward rotation from the set up position at the back of the backswing. The shoulders have fully rotated back when the hips rotate forward. If you just think about rotating the hips, the legs will do what they need to do. I don't think it's helpful to think about leg drive in this situation.

From the set up position at the back of the backswing, the forward swing is initiated by rotating the hips, which pulls the torso, which pulls the shoulders, which pulls the arm and racquet in that sequence of events.
What do you mean by that?

To me (everyone?):
The leg drive is critical to initiating hip rotation.... starts from the ground up
Put another way, I'd much rather get punched by a guy that is NOT driving with his rear leg, than a guy throwing a cross initiated with his rear leg.
When i throw a roundhouse kick, which is all about hip rotation, it all starts with my foot (ball of my foot) driving into the ground.
When I throw a ball (or pitcher motion), it's all about the leg drive starting the pitch
...and when i hit a forehand well, it's also initiated by my leg drive.
 
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