Friday, December 06, 2013

A Roadmap to a Hall-of-Fame Forehand: Part 10 - Review and Quiz

After a very long stretch of time focusing on coaching live players and getting their college (or pro) plans on track and in order, let’s return to our conversation about optimal topspin forehand mechanics by reviewing the key concepts we’ve covered thus far by completing a "quiz" to assess your mastery of the key concepts behind the execution of today's greatest topspin forehands.




The quiz questions are ordered in their “degree of difficulty”, with the initial questions being somewhat easier than the later ones. Also, feel free to consult previous posts at anytime so you will refresh and reinforce the correct concepts. 

Take your time over this holiday season to respond thoughtfully – and if you are truly expert in this subject, each (correct) response shouldn’t take more than a sentence or maybe two, if that.
And, as is our convention here in this part of the blogosphere, let's stick to anatomical terminology when describing and analyzing the movements involved in this vital element of pro tennis performance.

I believe this exercise will go a long way to either consolidating your knowledge and understanding of how to create Hall-of-Fame-worthy topspin forehand mechanics (for those of you out there who have been following this blog so patiently - for which I am grateful) or assessing if your current, theoretical/conceptual understanding of topspin forehand mechanics actually matches the reality demonstrated so spectacularly by today's stars (for those of you new to this blog).

I’ll post an answer key soon after the New Year arrives…
PART 1 – BASIC QUESTIONS
Why is spin production on the topspin forehand so critical to the effectiveness of this stroke in today’s pro game?

What impact location on the string bed is correlated with higher (top-)spin production compared with a “central impact” on the string bed?

What impact location on the string bed is correlated with lower (top-)spin production compared with a “central impact” on the string bed?


What is the position of the racquet face in the topspin forehand of the majority of the current ATP Top 10 at the end of their respective backswings? 

What is the position of the racquet face in the topspin forehand of the majority of the current ATP Top 10 just before they initiate their forward swing to impact?

What is the position of the racquet face in the topspin forehand of the majority of the current ATP top 10 at the moment of impact?


PART 2 - ADVANCED QUESTIONS 
True or False? The positioning of the racquet face alone is the most critical factor in determining overall topspin forehand performance? If false, explain what factors are also involved.

What is the optimal position of the racquet face in the following two points in the follow-through phase of the topspin forehand:

  • When the racquet arm first reaches shoulder height?
  • At the completion of the stroke?



What are the 2 fundamental changes in the overall racquet motion – swing path and racquet face position – in the topspin forehand mechanics employed by current Top Players compared with previous generations of tour-level players?




What is the position of the racquet face in the topspin forehand of the majority of the current ATP Top 10 in the “Impact Zone” – i.e. about 18 inches before and after ball impact on the string bed?



What is the difference (in percent) in the amount of (top-)spin produced at impact locations other than the center of the string bed?

Which of the following characteristics of a Top Player’s topspin forehand has the greatest influence on topspin production?

Grip?
Swing path of the racquet?
Arm Structure during the forward swing?
Racquet arm movement in the Impact Zone?
Position of the racquet hand just before the forward swing?
Position of the racquet hand at Impact?






Which of the following characteristics of a Top Player’s topspin forehand has the least influence on topspin production?

Grip?
Swing path of the racquet?
Arm Structure during the forward swing?
Racquet arm movement in the Impact Zone?
Position of the racquet hand just before the forward swing?
Position of the racquet hand at Impact?




BONUS QUESTION: Rank in descending order – from most important (“1”) to least important (“6”) – how important is each of the stroke characteristics listed above to topspin production in the forehand stroke?




What are the four (4) key characteristics of the racquet swing path used in the forward swing to Impact in today's Hall-of-Fame topspin forehands? 





What is the average ball speed of a Top Player’s topspin forehand when rallying in a tour-level tennis match?

What is the average ball spin rate of a Top Player’s topspin forehand when rallying in a tour-level tennis match?

What are the key anatomical characteristics of the topspin forehand mechanics that have been used to win 32 of the past 40 Men’s Grand Slam singles championships?

What specific anatomical characteristic is common to the topspin forehand mechanics of 39 of the same 40 male Grand Slam Singles Champions?

What is the most effective and efficient technology/methodology to analyze, optimize and correct tennis stroke mechanics today?
SUPER BONUS QUESTION: What do the following numbers mean?
In this exact order: 4, 40, -5, 4000, 80, 18, 12, 25, 7
Input these numbers in the empty fields on this webpage, record the result and explain what those results show and mean.
Happy Holidays to All and TTFN!


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Friday, February 15, 2013

A Roadmap to a Hall-of-Fame Forehand - Part 9: An Anatomical Comparison of the Federer and Djokovic Forehands

Last time, we showed you another example of the “resolving power” that becomes possible when describing (and then analyzing) tennis stroke mechanics using the standard terminology of anatomical motion. This approach revealed the extensive similarity in the forehand mechanics of the two most successful players of this era, Roger Federer and Rafael Nadal, which probably surprised a large number of players and coaches given the very different ways each Champion uses their respective forehands to dominate their opponents. 

Let’s now continue using anatomical terminology to describe the topspin forehand mechanics of the third, multiple (6 times and counting) Grand Slam Singles Champion and future Hall-of-Famer of this current era, Novak Djokovic —and – compare Djokovic’s forehand mechanics to the “standard bearer” of  this era, the 17-time (and counting) Grand Slam Singles Champion, Roger Federer.

And, before we get fully into things, we want to disclose here that as much as we tried to make sure that both players were executing the stroke shown here under the same playing circumstances, Djokovic’s impact point (around chest height) is different – slightly higher – than Federer (waist height). Where appropriate, we will tell you if the difference in their Impact position is the “cause” of any movement differences between the two players.

However, after observing hundreds of high speed videos of both Djokovic and Federer forehands, we have noticed that each player uses remarkably consistent mechanics when they make contact between ankle- and head-level—which is not surprising for players who possess “ultimate skill”, right?


1. Ready Position.

Virtually identical in their body positioning, except that Djokovic uses a different grip – one that’s more Western compared to Federer, with his index finger knuckle placed squarely on the bottom diagonal bevel of the racquet handle.  The difference in their grips explains why Djokovic’s racquet face appears to be in a more closed position at this stage of the stroke just before they initiate their respective backswings.



2. Breaking the Triangle.  

Already at this very early stage of the swing, although the anatomical movements each player uses during this phase of the stroke are qualitatively identical, you should begin to notice that there are pretty substantial differences in the extent (“size”) of their respective movements. Djokovic clearly moves his racquet hand much further upwards and backwards compared to Federer. A likely reason for Djokovic moving his racquet to a higher position, in this specific case is that he will be making contact at a higher point – chest-level – than Federer.

The difference in the grips used by each player also causes their racquets to “find” very different orientations at this stage of the stroke. The hitting surface of Djokovic’s racquet finds an open position (facing the sky, as well as the side fence) as a result of his rather extreme semi-western grip. In contrast, the Federer’s more eastern grip results in his racquet to find a more closed position such that the racquet face points towards the net.

Does this observation surprise you?

We find this to be an interesting observation given the fact that the vast majority of players and coaches understand and assume (presume?) that using a more western grip automatically results in the racquet face being closed at all phases of the swing, but the truth is that far greater control of the racquet face position – how closed or open it becomes –is optimally controlled by the various movements of the racquet arm, most importantly by controlling Elbow Pronation at the various phases of the stroke.

In fact, the specific advantage(s) of semi-western and western grips can be easily canceled out depending on which racquet arm movements are employed by the player during Transition and their forward swing to Impact.



3. Completed Backswing.

Both players employ nearly identical movements when they complete the backswing. Both players use Elbow Extension and Elbow Pronation to achieve the racquet arm positioning shown here. Both Federer and Djokovic use very similar movements of the hips and legs (due to the camera perspective and Federer’s stance, we couldn’t determine if his left hip was also externally rotated like Djokovic here) so they can generate and transfer elastic energy from the lower body to the upper body, greatly enhancing their racquet speed at Impact.

The difference in the (spatial) position and orientation of the racquet itself between the two is a product of the difference in the grips used by each player. The more western grip Djokovic uses – where the palm of his hand is placed into a position that is more under the racquet handle versus behind it—results in the hitting surface and tip of the racquet facing the back fence (away from the camera from this perspective) versus Federer’s more eastern grip—where the palm of his hand is positioned behind the racquet handle—that results in his racquet tip to point towards the side fence (and directly toward the camera from this perspective).

The second difference between these two players at this stage is the greater lateral bending of the spine Federer uses compared to Djokovic. In this instance, this difference in how each player uses their spine is most likely related to the (eventual) difference in the impact point for each player – around waist level for Federer and around chest level for Djokovic. As Federer lowers his racquet arm/hand to his desired starting position behind (and slightly below) the eventual impact point, he creates a slight (right) side bend in the process that will promote the rotational motion of the spine as he swings forwards to Impact.

One important similarity in the movements used by both Champions that should be noticed here is the fact that both show clear Elbow Extension of their racquet arm at this stage of the swing. This is the first of only two phases of their respective strokes (the other phase is their follow-through, post-Impact) where their racquet arm movements are similar. In only a few milliseconds from this stage, each Champion will move their racquet arms using very different movements to deliver their racquets to Impact.



4. First Forward Move (FFM).

At this critical juncture of the stroke, the key difference between the forehand mechanics used by these two Major Champions becomes detectible. This difference is the first visible sign that Djokovic is starting to bend his (right) racquet arm at the elbow – achieved by Elbow Flexion – whereas Federer maintains a much straighter racquet arm – achieved by Elbow Extension.

Milliseconds earlier, both players had relatively straight racquet arms when they completed their respective backswings. However, unlike Federer who maintains Elbow Extension from FFM through Impact, Djokovic changes the “structure” of his racquet arm using Elbow Flexion and Arm Adduction and maintains this bent-arm position-widely known as the “double-bend” position/structure-in the same FFM-to-Impact interval.

What is only rarely discussed—probably because it’s not very clearly understood—are the practical consequences of swinging the racquet forward to Impact using either Elbow Extension or Elbow Flexion. Does using Elbow Extension or Elbow Flexion have any influence on a player’s ability to increase the power, accuracy or spin production of their topspin forehand? Does racquet arm positioning make an observable or measureable difference in the power and control of the stroke? Or, is it really a matter of personal choice, “style”, or “idiosyncracy” that a player makes on their own that has no real effect on the actual shot?

One traditional teaching viewpoint is that Elbow Flexion enables the player to more easily control the racquet path as the player swings forward on, and therefore it’s believed to help players achieve greater racquet control at Impact. Swinging forward using Elbow Flexion is the preferred “solution” for the dreaded “Flying Elbow” – the uncontrolled Elbow Extension that’s commonly used by players who slap wildly at balls on their forehand side – that plagues both recreational and competitive players alike.

Over time, a topspin forehand forward swing that employs Elbow Flexion has been widely accepted as a “gold medal move” of a high-level topspin forehand, and also is considered to be a forehand movement that can be used to equal effectiveness by both highly talented and less-talented competitors alike (a movement that is apparently “insensitive” to a player’s ability level, as it were).

This perception of the “Flexion Forehand” – let’s use this term to shorten and simplify things to describe a topspin forehand that employs a pronounced Elbow Flexion to execute the forward swing to Impact from this point forward, as well as the term “Extension Forehand” to describe its counterpart – being the widely accepted “key move” as well as the dominant instructional “paradigm” for striking a world-class topspin forehand stands even today.

This instructional perception still stands even in light of the Grand Slam dominance that has been achieved in large part by the power and control demonstrated by the Extension Forehands of Messers Federer and Nadal.
When we look closely at the Grand Slam record since Roger Federer established himself as the standard-bearer of Grand Slam excellence in 2004, and classify the forehand forward swing type – Extension or Flexion  – used by each of the Grand Slam singles winners, we found the following:

Total Grand Slams contested (2004 – present): 37.

Total Grand Slam singles championships won by players using an Extension Forehand (Federer, Nadal, Safin and Del Potro): 29 of 37 or 78%.

Total Grand Slam singles championships won by players using a Flexion Forehand (Djokovic, Gaudio and Murray): 8 of 37 or 22%.

If you had to pick a forehand forward swing type based on the achievement level of its best practitioners, it’s pretty clear that choosing an Extension Forehand would be a very sound, logical choice.

Maybe this is also now a good a time as any to consider briefly what are other reasons for the teaching establishment’s apparent preference for advocating the Flexion Forehand over the Extension Forehand given that at the highest levels, players using an Extension Forehand have won three times as many championships compared to players with a Flexion Forehand?

One reason we can think of is based on another widely-held and widely-repeated tennis (and general athletics) coaching/skill-teaching paradigm that goes by the following adages:

“Simpler is better.”

“Having fewer moving parts means increased precision and accuracy – because less can go wrong.”

“A simpler, more compact movement is more efficient that a more complex, bigger movement.”

These sayings are in stark contrast to what we’ve concluded after studying hundreds, if not thousands of hours of video of elite athletes performing the skills that deliver world-class performance in their respective sports (beyond tennis, we also possess or have direct access to high-speed video from professional golf, baseball, track and field and soccer) the world’s elite athletes perform skills that require highly complex movements that are organized and integrated into very specific, defined and again, complex sequences.

The truth of elite sports performance is better stated as: “Complex is Better. Way, Way Better.”

Let’s now consider the other side of the (performance/achievement) coin…

In stark contrast to the optimal skills based on the optimal movements performed by the highest performers in their respective sports, “everyone else” who isn’t achieving world-class performance differ from the truly elite performer in two basic ways:

First, the non-elite use sub-optimal, insufficient (in number) or incorrect body movements; and

Second, the non-elite “organize” these flawed, individual movements into flawed or incorrect movement sequences.

And, third, “first” and “second” above also feedback onto each other and tend to either amplify performance limitations created by each other.

Bottom line? 

The non-elite are in the vast majority of cases are, at the very heart of things, missing outright performance-enhancing, performance maximizing movements used by a bonafide elite athlete.

Now, here’s the follow-up question to this observation that the skills produced by the world’s elite tennis athletes require more complex movements, but also more movements overall in number, rather than fewer movements to execute their world-class forehands, backhands and serves (and court movement, and just about every other physical skill):

How will players achieve higher (highest) performance levels if the predominant messages they receive are to “reduce and restrict” movements when the elite are doing nearly the opposite?

Next, ask yourself how the player – the student – will respond to such “instructions” on a practical, “real world” level…

They typically respond in one of two ways, as good students do, by following those instructions to the letter…

They respond by “subtracting” or eliminating movements in an attempt to reduce or remove “unnecessary” or “excess motion” – although they probably don’t understand or realize in which movements are, in fact, “necessary or essential” the first place. 

As a friend of mine puts it: 

Can you really make a (race) car go faster by removing or disabling 4 of the 8 available cylinders?  

 (And even if only flawed movements were removed, that doesn’t mean that they will be replaced by what’s truly correct or optimal!)

AND/OR

They respond by “restricting” movements – by reducing the size of a given movement at a given stage of the overall movement sequence used in a given stroke, by combining movements, usually into a “single, one-piece motion” instead of allowing a movement to happen in its “natural”, sequential pattern where there are, in fact, multiple movements that occurs in a specific sequence, much like the way space rockets find their way into space in multiple stages.

And again, this choice is typically made by the player without fully understanding what’s correct or optimal, so they don’t understand and can’t really predict accurately what the true consequences of their adjustments will be. As they say, little education can go a long way…

In either case, optimal mechanics will not be achieved because neither the correct movements are used, nor are those separate movement “components” used in the correct or optimal sequence. In other words, if you are seeking to maximize performance, going down the path of reducing or restricting motion more often than not leads to lower absolute performance levels rather than higher ones.

Therefore, a greater, “more complex” understanding of what the top players are doing may be important to those players (and their coaches) who didn’t win the “genetic lottery” like the Hall-of-Famers did.

In coming posts, we will identify and analyze the highly complex, performance-specific reasons or factors that account for the apparent dominance of the Extension Forehand (well, the Pronation-Extension Forehand, to be more precise).

On a “bottom line” basis, we can say right now that the main performance benefits of the Extension Forehand over the Flexion Forehand are fundamentally two-fold, 1) the increased ability to generate high racquet speeds in a efficient manner, and 2) increased topspin generation to increase shot control achieved by maximizing speed and control of racquet motion in the Impact Zone.

It’s actually quite a long, complex road to optimal performance and there are really no shortcuts…

Yet, if you are patient and determined enough, you can reap the rewards that only complex, specialized knowledge can deliver.



5. 20 Frames (95.2 milliseconds) before Impact.

Further differences in the movements used by Federer and Djokovic now begin to emerge in these early stages of the forward swing as each player accelerates his racquet toward Impact.

First, Federer maintains the Elbow Extension he established in Transition whereas Djokovic increases the extent of his Elbow Flexion and the angle of his upper arm and forearm is approaching a 90-degree, right angle (see photo 6 where his racquet arm angle appears to form a perfect right angle from this not-so-optimal camera perspective – although in reality, the angle between the forearm and upper is likely to be closer to 105 to 100 degrees).

Second, there is a visible difference in the extent of wrist movement between the two Champions. Federer appears to achieve a larger amount of Wrist Extension at this stage of the stroke than does Djokovic – even with the not-so-optimal camera angle, it’s apparent even to the naked eye the angle formed at the wrist between Federer’s racquet and racquet hand and his forearm is greater than Djokovic. While there is some controversy about the function of the wrist in the execution of a tennis forehand in among American tennis teachers and coaches, the same controversy doesn’t really exist in other tennis-playing nations.

 The main controversy in the US has to do with the basic question of what the wrist joint actually does in a (topspin) tennis forehand. 

Is the primary function of the wrist joint to create or enhance racquet speed, or is its primary function to control the direction of the outgoing shot?

Does the wrist perform other functions?

There is little, if any controversy about this particular subject when we understand the facts of anatomy and consider the long-available research conducted by the Germans and other tennis nations.
For a concise explanation of wrist motion in tennis strokes, we suggest you consult pages 30 and 31 in “Tennis Course: Volume 1 Techniques and Tactics” written by the German Tennis Association (“DTB”) and published in English in 2000 by Barron’s Educational Series (the original German version was published in 1995 under the title: “Tennis Lehrplan, Bard 1: Technik & Tactik).

The research shows the answer is both. There is a indeed a controlled movement of the wrist during the forward swing of a tennis forehand. (Notice we used the adjective “controlled” in describing wrist motion in the forehand!)  

In most cases, the initial movement is Wrist Extension where the racquet hand bends backwards, and then as the entire racquet arm is swung forwards to Impact (using Internal Rotation of the shoulder), there is a controlled – and in the case of Federer and Nadal, a rapid forward movement of the racquet hand even compared to many fellow top pros – or Wrist Flexion – into Impact and continues into the follow-through.

So, is optimal wrist movement in a tennis forehand an abrupt acceleration of the hand at the wrist joint timed to coincide with the very moment of Impact – i.e. a “slapping motion” where the racquet hand lags in maximum Wrist Extension and is then released suddenly and “spontaneously” at Impact – creating an overall motion much like a the way a slammed door swings on its hinges? No, definitely not.

Optimal wrist movement in a tennis forehand is a highly controlled movement that can be consciously controlled by the player – mainly by regulating the amount of tension/relaxation of the forearm muscles.

Does wrist movement contribute to racquet speed?

Yes, there can be a measurable difference in the speed in that the wrist joint achieves before, during and after Impact.

Does wrist movement contribute to controlling shot direction?

Yes, the top players demonstrate the ability to execute visibly different wrist movements during the milliseconds around Impact - generally speaking, more Wrist Flexion is detectible on crosscourt shots and less Wrist Flexion is used on down-the-line shots.

And, yes, the effects of wrist movement on the outgoing shot are themselves affected (perhaps even regulated) by other factors such as your grip (more eastern or more western), whether or not Elbow Extension or Elbow Flexion is used, and the racquet hand position – Pronated, Supinated or Neutral – at FFM. (All subjects which we will delve into in future posts…)

So from our point of view, the function of the wrist joint in the forehand is clear – especially from a practical and operational view, the most valuable view for students – and far from anything controversial. The question has been definitively answered long ago, in our humble opinion.

Third, the lower body movements of the two players differ – subtly – as well. Whereas Federer demonstrates movements – Knee and Hip Extension and Right Hip Internal Rotation – that show that he’s well into the process of transferring elastic energy from the ground through to his upper body through his legs and hips. Djokovic is only beginning to activate the same elastic energy transfer as there is only a small amount of visible Knee Extension and (Right) Hip Internal Rotation detectible at this stage. Much like Nadal in our previous post, Djokovic will “release” the elastic energy much closer to Impact (see photo 7 and 8) compared to Federer.

In theory, there might be some advantage of releasing that stored energy closer to the actual moment of Impact, yet, there may also be a trade-off as there is a physiological time limit where the maximum amount of energy can be released due to the time constraints inherent in the series of linked SSCs (Stretch-Shorten Cycle, a neurophysiological phenomenon discussed in an earlier post) of the musculature of their legs, hips and core.

Finally, a fourth difference between the forehand mechanics of these two Champions at this stage of their respective strokes has to do with the extent of their use of the potential SSC of their rotator cuff muscles

This difference has to do with the fact that Federer’s Elbow and Wrist Extension at FFM – all while maintaining Elbow Pronation – initially results in the External Rotation of his right shoulder. The External Rotation of the right shoulder produces a countermovement triggers further SSCs that ultimately increase the contraction force of the Internal Rotation of the right shoulder. And, it is the (enhanced) Internal Rotation of his right shoulder that is the “engine” that powers his forward swing to Impact.  

In contrast to Federer’s Elbow and Wrist Extension at FFM, Djokovic’s racquet arm begins to move from Elbow Extension toward Elbow Flexion, and by doing so, greatly reduces the extent of External Rotation in his right, hitting shoulder – thereby reducing the stretching of his entire rotator cuff complex – and possibly reducing or inhibiting further SSCs in those muscles. Ultimately, without triggering those SSCs, there will be little, if any (potential) enhancement of the contractile force produced by the Internal Rotation that drives the forward swing.

In fact, you can probably feel this for yourself, finish your backswing and make sure you pronate your elbow. Then begin your forward swing by adducting and flexing your racquet arm and focus your senses on what’s happening in your rotator cuff – when you adduct your arm, you automatically initiate Internal Rotation of the shoulder, and “minimize”, or perhaps even elminate External Rotation – the linked countermovement that triggers SSC. Therefore, those players who have a Flexion Forehand end up leaving the powerful SSCs of their hitting shoulder largely untapped.

Maybe the important follow-up question for those players who use a Flexion Forehand then becomes this: is it possible to compensate for the forfeited power enhancement from the shoulder SSCs using another body movement?

Again, as my friend puts it:

How can you increase speed or power by disabling or disconnecting – voluntarily – the very cylinders in the "engine" that produce speed?




6. 10 frames (47.6 milliseconds) before Impact.

As the players get even closer to Impact, notice that the differences in the racquet arm movements are maintained. Federer maintains Elbow Extension while Djokovic maintains Elbow Flexion. Federer’s Wrist Extension is far more pronounced than Djokovic in its apparent extent and Roger’s forearm muscles visibly show much greater stretching and “tension” at this stage of the stroke.

You can feel the difference for yourself. Begin by placing yourself into the positions that Federer uses at FFM and in the early stages of his forward swing to Impact.

First, pronate your elbow so your palm faces the ground. Next, gently extend your elbow – straightening your entire arm and then extend your wrist so the hand hinges backwards. Now start swinging your entire arm forward and maintain your Elbow Extension… Feel the pronounced stretching of your forearm muscles? This stretching of the forearm muscles is what creates a countermovement that triggers SSCs which increase the contraction forces that are transferred to impact using the controlled Wrist Flexion that is integrated into the forward swing to Impact.  

Now compare the sensation in the forearm muscles when you put your racquet arm into the positions that Djokovic uses at FFM and in the very early stages of his forward swing. First, pronate your elbow so the palm of your hand faces the ground, then extend your elbow slightly – straightening your entire arm – and then extend your wrist so your hand hinges backward. Now, as you start swinging your entire arm forward, instead of keep the racquet arm extended at the elbow, pull the upper arm section of your upper racquet arm inward toward your body so your flex your arm at the elbow. Do you notice that you feel much less of a stretching sensation in your forearm muscles? (As well as the fact that the active contraction of your biceps muscles can also cause your arm to decelerate slightly despite the sensation of added “strength and stability” at Impact you get when you flex that “24-inch gun”…)

Although there are other stroke experts who are trying to make the argument that the wrist really doesn’t create a countermovement that triggers SSCs in the forearm muscles that could contribute additional muscle contraction forces that could be transferred into Impact, don’t the sensations of the movement “experiment” you’ve just performed tell you otherwise?

At the very least, Elbow Extension creates an additional source of elastic energy – that can be coupled that is already moving through the body toward Impact from the increased stretching of the forearm muscles (that optimizes muscle length-tension properties), ligaments and tendons  (particularly in the tendons) themselves, that could be transferred through the arm and racquet to the ball.

Elbow Extension also enables its practitioners to create a slightly larger overall swing radius – that creates higher racquet speeds – because extending the elbow allows the player to keep their upper arm extended further away from the body.
In contrast, many high-level players – mainly in the national junior to Futures levels – who Elbow Flexion to swing their racquets forward to Impact often pull their elbows tightly into their body, which decreases minimizes their “swing radius” and consequently inhibits racquet speed (although their brains will devise workarounds to compensate for those losses by increasing the speed of upper body rotation and other movements – we’ll discuss these compensatory movements down the road as well).

And to show you the fact that” not all Flexion Forehands are created equal”, Djokovic and other top pro players who use a Flexion Forehand tend to maintain a sizeable gap between the racquet arm elbow and their upper body during the forward swing, rather than “jamming” their elbow into their hips so that they can tap the benefits of having a larger swing radius (and again, we’ll mention here that Djokovic and other “talents” probably perform this move instinctively, such are the “privileges” of being born with such enormous natural abilities!).


Djokovic. Note the space between the hitting elbow and his body.


Ferrer. Again, notice the space between the right elbow and his body.

Bellucci. Where's the space between his elbow and body? What happened? Why?

Raonic. Again, a much smaller space between the hitting elbow and body compared with Ferrer and Djokovic. 

(Now, you might want to ask the question that goes like: if so many players end up using non-optimal movements that actually limit or inhibit their ability to maximize racquet speed/power, how do those players generate a powerful stroke? Another important question that needs to wait for a future post…)

An important similarity to notice between the two Grand Slam-grade forehands here is the shallow racquet path that each player uses to deliver the racquet to Impact. Specifically, notice how both Federer and Djokovic start their forward swings with the racquet positioned only a fraction below the intended contact height – for both forehands shown here, the top edge of the racquet is aligned just below the path of the incoming ball. This shallower racquet path combined with the increased forward face tilt is how today’s top players create a shot that has a lower, more driving overall trajectory without sacrificing topspin for maximum shot control.

7. Impact.

At Impact, both players continue to maintain the body positioning/movements that each established shortly after FFM. Federer’s racquet arm remains extended from the elbow, while Djokovic’s racquet arm remains flexed – forming the characteristic “V”-shape of the racquet arm of a Flexion Forehand when you view Impact from the side view.

We also how each player has rotated their entire upper body into impact as both the chest and the navel of both Federer and Djokovic are now pointed at the net. We also see the first indication of Right Hip Extension (along with the straightening of his right leg – Knee Extension) from Djokovic that indicates that the elastic energy he produced using his lower body is (now) being transferred to his upper body.

We clearly see visual evidence that both players are consciously pronating their racquet elbow prior to Impact (image 6), at Impact (image 7), and continue this Elbow Pronation well into the follow-through phase of the stroke (images 8 & 9). Below, to show you the Elbow Pronation that both Federer and Djokovic perform in the moments surrounding Impact, we measured the angle of the racquet face at 4.8 millisecond intervals just before Impact, at Impact and after Impact. Notice how the racquet face angle remains tilted slightly forwards just prior to Impact and at Impact, and just 4.8 milliseconds after Impact, the racquet face tilts even further forward.
When the ball impact is on the equator of the racquet, the racquet face remains stable - no additional forward or backward tilting of the racquet face occurs in the scant milliseconds after Impact- as is shown below. Therefore, in the two sequences below, any racquet face motion is created by the player himself.
Federer:


Djokovic:

However, we find it even more interesting that there is a clear difference between Federer and Djokovic in the amount of forward racquet tilt that each player consistently achieves at impact. Federer tilts his racquet face much farther forward than Djokovic does at Impact in this specific stroke comparison – as well as when we’ve compared any two of the dozens of Federer and Djokovic’s ultra-slow motion forehand impacts we have in our video archives.
When we measured the forward tilt of the racquet face for the various players who use Elbow Extension in their forward swings, we found that, at Impact, their forward racquet tilt is generally greater than 10 degrees. In contrast, on average, the forward racquet tilt of players who use Elbow Flexion in the forward swing at Impact much smaller, typically only in the 4 to 5 degree-range. (Djokovic tilts the racquet forward more than most top pro players who use a Flexion Forehand, typcially his forward racquet tilt at Impact is in the 7-8 degree range.) That’s 50% less forward tilting that can contribute to topspin generation!

And what’s maybe more interesting is our observation that players who use either an extreme semi-western or full western grip where the palm of the racquet hand is placed mainly underneath the racquet handle typically demonstrate the smallest amount of forward racquet face tilt – typically only 1 or 2 degrees forward. (Now, doesn’t this observation beg one to question the widely held perception that western grips deliver “maximum” topspin generation?)
And, if you are also wondering, in this vein, the Nadal forehand grip isn’t really a western grip as many believe. At Impact, if you observe closely enough, you will see that the palm of Nadal’s racquet hand is very much behind the racquet handle – like Federer – versus underneath the racquet handle as it would be for a “true” western grip (for comparison, see current Top 30 ATP practitioners of full western grips: Kei Nishikori, Phillip Kohlschreiber, Jeremy Chardy and Jurgen Melzer.)

In this specific player-to-player comparison, Roger’s racquet face is tilted twice as far forward compared to Djokovic at the moment of Impact as shown here. We also need to keep in mind that there also exists their ability to control and therefore, vary at will, the rate and extent of their Elbow Pronation (as well as every other movement in their stroke repertoire – such is the nature of the physical gifts they were born with) in the Impact Zone.
So, there is “natural” variation in their body and racquet movements from (individual) stroke-to-stroke, depending on the playing situation they face and the “tactical” choices – more speed, less speed; more spin, less spin, more angle, less angle, etc. – they make in response to what they see during live play. Regardless, there is a fundamental and remarkable consistency to the way they execute their skills – we should expect such capabilities given they are such amazing athletes – that makes it, in many ways, easier to determine and understand how and why they achieve the results they do given how they control their body and racquet.

In our view, this difference in the extent of the forward tilting of the racquet face at Impact explains the difference in forehand topspin rates demonstrated by each player – 2,500 RPM for Federer and 2,100 RPM on average for Djokovic – we’ve observed when they play on North American hard courts.

After analyzing the racquet motion in the moments just prior to and just after impact for all of the top players we have in our extensive stroke video archives, we began to notice an interesting correlation between the amount or extent of racquet face tilt at Impact and whether or not a player uses Elbow Extension or Elbow Flexion in their forward swing.
The correlation is that the players with Pronation (at FFM, or FHT-2)-Extension Forehands demonstrate noticeably greater forward racquet tilt compared to players with a Pronation-Flexion Forehand – take a look at the following images where we measured the amount of forward racquet face tilt at Impact for players using an Extension Forehand versus players who use a Flexion Forehand:



(Note this Federer-Djokovic Impact image is taken from a different stroke by each player than the one used for our main comparison in this post!)


The same difference in forward racquet face tilt between the Extension and Flexion Forehands appears to hold true even for Roger himself in the rare times he finds himself setting up too late and too close to the Impact point and is forced to use Elbow Flexion to make decent contact with the ball:


There is a logical, anatomical explanation for this apparent correlation between the extent of racquet face tilt at impact and whether the player employs Elbow Extension or Elbow Flexion in their forward swing that itself will fill its own, separate post in the very near future.

One last question that we feel is appropriate to pose here in our discussion of the body movements used by Federer and Nadal at Impact is this: why do so many players today use Elbow Flexion at all to swing the racquet forward? Part of the answer certainly has to do with players, teachers and coaches have only an incomplete understanding – at best – about how the body and racquet motion influence the speed, spin and direction of the outgoing shot.

Even the sports science community and their elaborate and expensive 3-D motion analysis systems (typically costing $100K or more) generally only have a very limited perspective about stroke mechanics because they – biomechanists – are primarily interested in studying the forces and speeds generated by the body itself  and the great majority of them do not correlate their findings with the actual output of those bodily forces and velocities on the shot that results from them.
The vast majority of biomechanists do not measure and are apparently unconcerned or disinterested about the spin, speed and trajectory/direction characterstics of the ball itself – the very product/outcome of those body movements – because, quite frankly, they aren’t all that interested in what happens to the non-human motion involved in striking a tennis forehand  - i.e. the motion of the racquet, strings and most importantly, the ball.

Which may be one big reason why the contribution of biomechanists are often viewed with great skepticism by players and coaches because many biomechanists disavow interest and/or don’t measure or understand what the ball does after the player strikes it.
Their view starkly contrasts the view of most players because for players, what the ball does is arguably THE critical factor in defining their performance.

Could there be a specific performance-based reason or benefit for shortening the overall radius of the forward swing – which, according to the laws of physics as most understand them—causes decreased racquet speed, as well as limiting the amount of forward racquet tilt at Impact that would increase or enhance topspin generation?

Could it be possible that Elbow Flexion is a “mandatory” component of most topspin forehands today based on anatomical or biomechanical needs and its use has nothing to do with “style” or “instruction”? 

Stay tuned for that discussion as well.

8. 5 Frames (23.8 milliseconds) after Impact.


9. Follow-Through (Arm at shoulder height).

10. End of Stroke.

The anatomical differences between the two players that persisted from Transition to Impact now largely subside and both players use virtually the same movements starting from the early moments through the completion of the follow-through phase of the stroke. Djokovic’s racquet elbow now begins to extend causing his arm to straighten slightly. The combination of (Right) Wrist Flexion, Radial Deviation and (Right) Elbow Pronation that started at or just prior to Impact continues and eventually creates the so-called “windshield wiper” motion that is a common stylistic element of the follow-through of most topspin forehands today.

This post-Impact Elbow Extension together with Elbow Pronation enables Djokovic to swing the racquet such that it follows the path of the outgoing shot – thereby creating the “extension down the target line” that is so coveted by most teachers and coaches – before he is forced to bend his arm – Elbow Flexion – a  second time to complete his follow-through and overall stroke (image 10).

Does late, post-Impact elbow movement have any influence on the outgoing shot? In our humble opinion, the oh-so coveted “extension down the target line” has about as much influence on the shot as the post-Impact, after-the-fact Wrist Flexion/Radial Deviation movement that Lleyton Hewitt employs in his topspin forehand follow-through. Meaning, this movement is mainly cosmetic or stylistic and has little or no influence on the outgoing shot itself.

Another key similarity in the forehand mechanics of these two Champions we should also emphasize here is to notice that both players swing the racquet on an overall path where their racquet hand rises no higher than around shoulder level on the vast majority of strokes. With the exception of the odd, “reverse” forehand where the racquet ends up finishing overhead, the “low finish” of the racquet hand is the result of the much shallower, upward swing path that most top players use today to create the low-trajectory, high-spin shot that characterizes the dominant shot type used during top-level matchplay.

TAKE HOMES?

In previous posts, we established that Elbow Pronation at FFM (First Forward Move) – aka, FHT-2 – is the optimal method for executing the critical transition from the backswing to the forward swing in executing a world-class forehand. And we also clearly established that FHT-2 is the dominant type of forehand transition among the vast majority of (male) Grand Slam Singles Champions in recent history.

In this post, we compared and contrasted the forehand mechanics of Roger Federer and Novak Djokovic with the intention of  bringing your attention to another very important movement in the execution of a Grand Slam-caliber topspin forehand – using Elbow Extension, rather than Elbow Flexion, to swing the racquet forward to Impact.

While Elbow Flexion has been the far more common movement used to generate the forward swing to Impact by the great majority of very successful tennis competitors from junior tennis, all the way to the Pro Tours from the late 1970s until today, including a large proportion of Grand Slam Champions up until the early 2000s, more recent Grand Slams have been dominated by players who swing their racquet forwards to Impact using Elbow Extension.  

By analyzing the racquet motion that is produced by top players who use Elbow Extension to execute the forward swing versus those players who use Elbow Flexion, we have found that the use of Extension or Flexion has a visible and direct effect on racquet motion in the moments before Impact, at Impact, and after Impact.  Players who swing the racquet forwards using Elbow Extension (in combination with FHT-2!) create greater forward racquet tilt at Impact – such that topspin generation is enhanced for these players compared to those who use a Flexion Forehand (even if they use the optimal transition type, FHT-2, in combination).

Speaking of maximizing topspin production, we found this very interesting magazine photo sequence from our archives (Tennis Magazine - Japan (July 1991), if I recall correctly).
It’s a topspin forehand photo sequence of Boris Becker (top) and Sergi Bruguera (bottom) from Roland Garros in 1991. Is it a coincidence that one of the most heavily-spun topspin forehands of that era (or of any other era, frankly @ 3,500 RPM) struck by Bruguera was achieved by using Elbow Extension in the forward swing?



What’s the whole point of maximizing topspin production?

When topspin production is enhanced, the player’s capability to control the speed and direction of their shots improves as a direct result. And, their shot consistency increases as well. While Elbow Extension may also contribute enhanced elastic energy production and transfer by the racquet arm itself that could also increase a player’s power potential by delivering higher racquet speed, our current thinking about how the Extension Forehand has contributed to the Grand Slam domination of its best practitioners, Roger Federer and Rafael Nadal, is this:

Striking forehands using Elbow Extension has given these two players a clear edge over their rivals by delivering higher levels of shot control and consistency by enhancing their ability to produce large amounts of topspin without sacrificing (“trading off”) ball speed.

In our opinion, it is this enhanced topspin production capacity, as well as increased racquet speed capabilities, that can be achieved by using Elbow Extension to accelerate the racquet toward Impact that appears to have delivered that “edge” that Roger Federer and Rafael Nadal have wielded over their rivals in the past decade to Hall-of-Fame effect.

In tennis, maximizing speed without maximizing control simultaneously is a playing and instructional philosophy that leads to only one ultimate destination: the proverbial “scrap pile” and all the unnecessary frustration and bad feelings that come with it.

TTFN!

P.S.: We wanted to take this moment to thank all of you out there who have taken valuable time out of your day to explore and begin drilling down into the amazing and often mystifying world of world-class tennis with us.

We have noticed that our readership has been grown substantially over recent months, and we have been receiving an increasing number of emails asking us if we provide instruction in the stroke concepts and movements we discuss in our blog.

The answer is YES, we offer instruction, coaching and consulting in all aspects of high-performance tennis development from stroke mechanics to mental skills training, as well as career and college planning.
We have over 15 years of experience in high-performance tennis development and we offer our services via:
  • Traditional, live, in-person sessions from our Boulder, Colorado base (or by traveling to where you train as we have done for a growing number of national junior competitors, tennis academies, NCAA teams and ATP/WTA competitors), and
  • Online video analysis and coaching/consulting using the power of technology and the Web.

We want to also mention here, that as much as commenting on blogs is the most common way in this Internet Age to pose questions you have about what we cover in our typically, very detailed posts, we encourage you to pose your questions directly to us by email as well.
(Let us also mention this... While we are focused on the details of elite tennis performance, we want to help whomever is interested in raising the level of their game, no matter what your current level may be!)

When you write us an email, we can reply with a more in-depth response that goes beyond the brief, “comments section reply”.

Send us an email if you are interested in our online or in-person instructional and coaching services, or have questions about what we discuss in the blog. We want to hear from you!

Email us at: tennisspeed@gmail.com

for more details on how we can help you achieve what you are seeking in tennis.
Thank you very much again for all of your interest in our blog, and just to let you know, we still have a LOT of ground to cover if you are seeking the knowledge that's behind the development of the sublime tennis skills of the world's greatest players.
(Gee whiz…We haven't even started discussing the details of optimal topspin and slice backhand mechanics, much less the intricacies of serve mechanics.)

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