How to visualise the lag and whipping motion on the forehand and 2 handed backhand.

[Chas Tennis]

The stretch shortening cycle is a way to transfer kinetic energy (1/2m x v^2) into elastic potential energy. It makes it easier to load up that energy to save it for a later time frame and release it.

As for passing on momentum from one link to another, I don’t think that is entirely transferred. This would be like saying that if a person was sitting on a merry go round as the merry go round had them moving at 20 m/s, and the merry go round just stopped, that the person would fly off at greater than 20 m/s. that is not consistent with observed objects rotating around an axis. They are known to fly off at the exact tangential velocity they had before the string was cut. The momentum tied up in the weight and moment of inertia of the merry go round is transferred to the breaking system used to slow (stop it). Now, if someone wants to say, “Ya, the breaking system. The extension on the next limb is the breaking system, and that is where the momentum goes.” No. That is where some of the momentum goes, not all. The inner part will slow because some of that momentum will be tied up in the new addition to its moment of inertia. It is likely that, by most evidence, kinetic energy is the currency for transferring speed in segments, not momentum. If you look at all Langrangian equations, they use kinetic energy terms to describe double pendulum motion. Other more common evidence for momentum of one link not being fully transferred to the next link is the summation of speeds description for the kinetic chain.

Merry Go Round analogy? Where is the elastic energy storage on a Merry Go Round analogous to what muscles have? There is none. I discussed an accelerating system with elastic storage not a MGoR.

If the MGoR had elastic supports for the rider and it first accelerated to stretch the supports and then stopped (decelerated) the rider would look much like the upper arm during the forehand, the rider would lag during acceleration and then be propelled off the MGoR and the velocity could exceed the MGoR's velocity, I think. ?

Now I'm not so sure about the rider's maximum speed with acceleration and rider with elastic supports .........

In any case, a MGoR does not have an elastic storage component holding the rider's mass.

Usually, we don't think of the MGoR as strongly accelerating because it accelerates gradually. The acceleration is harder to see than the velocity.

Acceleration vs Velocity

 

[oserver]

Oh boy, no its not.

Upper body is clearly rotating PRIOR, ON and AFTER contact. There is no forced abrupt stop, there simply IS NOT. Sometimes the players do it, but its situational, but on most forehands your driving your body mass around.
The lag and snap does not happen because you stop your upper body for godness sakes, the lag happens because your wrist is relaxed, the racquet gets dragged and has weight on the tip, and the release happens because the arm with racquet in hand reaches the maximum point infront and starts curving inside like a car draging a weight on a rope, so it gets flung forward, not because the body stops.

Im done arguing its pointless, I suggest you watch the videos above in super slow motion by slowing them down further to 0.25x, if you still don't see the body rotating through contact then I guess in your mind it just doesn't.

Agreed. From your photos, there is no abrupt stoping of body turning; it's the range of turning is more obvious at shoulder level than at knee/waist level. There is no way to stop in the middle of rotation, either intentionally or unintentionally. It's basic physics. Just think about the followthrough, not in terms of arm and racket, but in term of the whole body of the player. How do you stop for a moment and go into the followthrough?

If there is a brief moment of stopping (slowing maybe the better word), it's caused by the ball collision on the racket that will slow down the body rotation somewhat, then when the ball leaves, the followthrough of racket/arm/body start.

It's the passive arm, loose wrist at extension state and cross body swing (not the classic drive through the ball swing) to make the lag possible. Thinking that one can stop the motion somewhere won't help anything at all. There is no short cut in terms of training to get to the professional level.

 

[Chas Tennis]

...........................

"To fully release the upper arm and its stretched muscles you cease the acceleration. The uppermost body turn can continue. "

The upper most body does not continue, it stops to release the arm and it is the arm that gets released forwards. ............

The uppermost body may stop or continue rotating depending on how the forehand is performed. I don't know how many high level forehands 'stop' uppermost body rotation. I'm sure many videos show stopped, but what %? Future studies of many ATP forehands can estimate those percentages.

Maybe if uppermost body acceleration were stopped but uppermost body turn were continued it would be a plus. ? All in several milliseconds. ?

If you continue to rotate the shoulders you are still stretching the muscles and you havent released them.

I don't agree. That was my point of acceleration vs velocity. If the line between the shoulders rotates without acceleration there are no forces to stretch the muscles (ignoring any centrifugal forces).

If you always distinguish between acceleration and constant velocity in what you write it helps to make clear and understand the forces and mechanics. F = mA

 

[Kobble]

If a person was sitting on a merry go round with it’s hips bound to the seat, a sudden stop would cause the upper body fall, where the head would initially move faster than 20m/s. That’s what happens with hand being the end of the arm, and with racquet head coming from deep lag. The former is additionally enhanced with SSC shorten phase, the latter may or may not be deliberately restricted as JY pointed out.

Do you have any physical experiments that show the velocity gain on video?

For those wondering, that still isn't transferring extra momentum from the merry go round. Just leveraging the momentum the person possesses as a separate system, and leveraging that in an angular fashion to finaggle more kinetic energy out of it.

Kinetic chain is a concept, not a physical law/proved theory/etc., something you could apply like a formula. I find SSC mechanics to be the most pure demonstration of the concept, where actual storage of energy takes place. In other cases it could be describing actual decrease in losses due to counteraction of power sources, and lifting limitations, couldn’t it? FH sequential, segmented mechanics is actually a great example: when a player uses best timing instead of trying to use all power sources (leg drive and core muscles to move forward and rotate torso, chest and shoulder muscles to swing arm forward), he achieves better outcome. Same for serve, first loading the shoulder and setting proper body structure, then firing ISR to accelerate the racquet, then pivoting it on top of the motion to direct achieved RHS.

Well, it is all governed by classical physics laws. What you were describing was something similar to Kepler's Law. The momentum of a piece of an object stays the same, but the radius changes, creating more velocity. The momentum of the object rotating around and axis is tied to the area it sweeps out over in a given period of time. Cut the radius, and the object increases tangential velocity to cover the same area.

There is alot I am trying to figure out

 

[Chas Tennis]

We are all agreeing on the important part ... passing on momentum to the arm after shoulders hit end of range . According to Curiosity... the pros use the tuck of off arm to impede rotation ... which sounds pretty abrupt. How abrupt doesn’t matter to me ... I was very surprised at the shoulder turn pause when I first noticed it. On pro BHs ... 1hbh and. 2hbh ... the pause happens around chest pointing at left net post.

What did Curisoity say about the off arm? Forehand?

 

[Chas Tennis]

........

There is alot I am trying to figure out

I'm still trying to figure out the Merry Go Round and see if it can be used as a simplified learning model to understand the forehand.

The MGoR is somewhat analogous to the uppermost body (line between the shoulders) and the rider mass is somewhat analogous to the moment of inertia of the upper arm, arm and racket. The rubber sling is analogous to the elastic component in stretched muscles, Titin. But there is some type of nerve control of forces from Titin.

There is a giant sling shot on a Merry Go Round and a rider is in the pouch of the sling shot, with two giant rubber slings. The MGoR starts from rest and begins accelerating the mass of the rider. This acceleration stretches the giant sling shot rubber slings. The stretching will slow and stop when the elastic forces of the rubber slings increase to equal F = mA. As long as constant acceleration continues the rider will go around the MGoR in a giant sling shot with stretched rubber slings at a fixed length, L-- F=mA = hL (Hook's Law gives the force of the rubber for a given length, L, h is Hook's constant for the rubber slings)

If the acceleration is entirely stopped suddenly, the MGoR's rotation velocity in then constant, the stretching forces will stop and then the rider will be propelled forward at a higher velocity than the MGoR's rotation velocity. If the acceleration is only decreased the rubber should shorten and propel the rider forward with less velocity than stopping acceleration, but more velocity than the MGoR. (Is this a model for stopping uppermost body acceleration? - you get the velocity of the uppermost body turning plus the extra acceleration from stretched shoulder muscle forces on the upper arm.)

If the MGoR were completely stopped suddenly, a very large deceleration, zero velocity, including a stopped sling shot, then the rider and rubber sling would still be moving with the MGoR's original speed toward the now stopped sling shot. What effect would the stopped sling shot have on how the still moving rubber sling accelerates the rider? How does the stopped MGoR model the forehand? Stopped shoulder is a view that some posters have for the forehand.

 

[tennishabit]

Your talking like your right and im wrong and I should accept that your right and get to understand these key things as you say.
But why would I find it useful to get understanding of these key things when my opinion is that these key things are wrong?

You showed two pictures of Serena and Novak at two COMPLETELY different phases of the stroke to prove some point I don't understand even.

If you look at the same time and frames then apart from a few differences like novak having his left arm parallel to baseline and serena having it into the court etc.... there doesn't appear to be ANY significant difference in any part of the body or swing or stroke between the two forehands:

gr8 pics n so we always said 'a pic's worth 000s words'...........lololololol watched mixed doubles n f/m trading ground strokes to each n seems very little differences there except f/m serves. remember a fh/bh speed stat online showing only a few kms/hr less for wta-ers.........................

 

[Dragy]

Your talking like your right and im wrong and I should accept that your right and get to understand these key things as you say.
But why would I find it useful to get understanding of these key things when my opinion is that these key things are wrong?

You showed two pictures of Serena and Novak at two COMPLETELY different phases of the stroke to prove some point I don't understand even.

If you look at the same time and frames then apart from a few differences like novak having his left arm parallel to baseline and serena having it into the court etc.... there doesn't appear to be ANY significant difference in any part of the body or swing or stroke between the two forehands:

Don’t you see how on second frames Nole is more rotated forward while his arm and hand and racquet are still farther back? I cannot show you same picture by Serena (torso facing target, arm still fully back) because she never reaches it. However I can show you similar picture with literally every ATP player.

 

[rkelley]

Someone earlier mentioned Brian Gordon and his video below breaks down exactly whats happening.

At the beginning he talks about the 3 types of swing.

Type 1 the "classic" Serena type is where the body/shoulder/arm rotates in unison with each other in 1 continuous smooth kinetic chain.

The type 3 ATP swing is segmented where the body and arm move independently of one another. He even talks about the explosiveness of the kinetic chain and that its different in that it goes one after another, boom, boom, boom.

This shows how the kinetic chain and its timing, between classic and ATP forehands are different.

If you fast forward to 20 minutes, from there he then explains why the fast unit turn separated from the arm works - what you are doing is creating a stretch-shorten cycle.

He gives an example where he tries to pull his arm in using his bicep muscles. He then gets someone to resist his arm and then they pull away - his arm goes flying.

By rapidly rotating the body and leaving your arm lagging behind you are stretching the muscles in your arm and shoulders. As you release it your arm goes flying forwards.

A rapid body rotation is akin to stretching those muscles and the rapid stopping is akin to letting those muscles go.

So a rapid unit turn and stopping is the way to think about how your body should move in relation to your arm (not in unison, but separate), and the Brian Gordon video explains exactly why.

If I understand Brian Gordon's point on generating racquet head speed (rhs), he's saying that the rhs speed is generated by a stretch shortening cycle (SSC) in the arm. I'm going to respectfully disagree with this. The high rhs in modern the fh is generated primarily by conservation of momentum.

As you initially swing the racquet into the ball it's NOT a fast, super high powered part of the swing. Your arm is NOT lagging way behind you with a bunch of SSC in the shoulder. Your arm is really weak in that position and trying to develop a lot of force at the shoulder on a straight or mostly straight arm isn't going to work very well. What we see in the videos is that the pros are rotating their bodies and their arms are mostly moving along with their bodies. The arm is pretty passive.

You need to have the lag, i.e. the wrist extended back, that everyone here has discussed during this part of the stroke. You can develop the lag as part of the swing (a lot of players do this), or have the lag mostly there at the start of the swing. I don't think it matters because I don't think there's much SSC in the wrist. You're allowing your wrist to extend and create the lag. It mostly a free hinge.

The trick here is that now you have create the whip that forces your freely hinging wrist to accelerate the racquet into the ball. @5263 talks about pulling the arm across back to the center. @a12345 was talking about stopping the shoulder rotation (which is more a result than a forced stop of the shoulders I think). The key is that you're changing the motion of the hand, and doing it in a way that the racquet has to accelerate forward in order for momentum to be conserved. It's a whip.

Have you heard the teaching that you should swing out away from your body? It's a good teaching construct I think. When you do that eventually you get to the point that the arm can't go out any further because it's still attached at the shoulder. When you hit that point then the racquet will accelerate forward to conserve momentum, especially if you pull in on the racquet at this point.

Look at the straight arm fhs (Fed, Nadal, Verdasco). A straight arm is really weak in every direction except one, pulling back in towards the body. Those fhs work because the players allow their wrists to freely lag and then basically pull back in across the body to trigger the whip.

When @JohnYandell talks about holding the wrist back I think that's a thing that's happening because it helps you control when the whip happens.

 

[Dragy]

However I can show you similar picture with literally every ATP player.

A bit different angle, but still cool to see:

And I can go on forever.

 

[tennishabit]

A bit different angle, but still cool to see:

And I can go on forever.

how abt dis1:?))))

https://www.facebook.com/TennisUnit...K75U8K84DC0WHvcgK4nRsx_9Q9_d0ph4eI6gc&theater

boyohboy, 'snap' shot of future top atp in very nice 'laggy' 'butting the ball' way......................

 

[Raul_SJ]

If you look at the same time and frames then apart from a few differences like novak having his left arm parallel to baseline and serena having it into the court etc.... there doesn't appear to be ANY significant difference in any part of the body or swing or stroke between the two forehands:

I also am not seeing much difference between Novak and Serena.
One can have that lag and laid-back wrist with Serena's WTA-style as well.

free picture hosting

 

[FiReFTW]

Don’t you see how on second frames Nole is more rotated forward while his arm and hand and racquet are still farther back? I cannot show you same picture by Serena (torso facing target, arm still fully back) because she never reaches it. However I can show you similar picture with literally every ATP player.

Dunno, I never really went that much into such details, not even sure how I do it

Heres my fh

 

[a12345]

The uppermost body may stop or continue rotating depending on how the forehand is performed. I don't know how many high level forehands 'stop' uppermost body rotation. I'm sure many videos show stopped, but what %? Future studies of many ATP forehands can estimate those percentages.

Maybe if uppermost body acceleration were stopped but uppermost body turn were continued it would be a plus. ? All in several milliseconds. ?



I don't agree. That was my point of acceleration vs velocity. If the line between the shoulders rotates without acceleration there are no forces to stretch the muscles (ignoring any centrifugal forces).

If you always distinguish between acceleration and constant velocity in what you write it helps to make clear and understand the forces and mechanics. F = mA

A fast body turn is acceleration.

Acceleration is change in speed / time. When you turn your body quickly over a short space of time you are accelerating. If you stop turning and reduce your speed quickly over a short space of time you are decelerating.

 

[Dragy]

Dunno, I never really went that much into such details, not even sure how I do it

Heres my fh

You are speeding up your arm like a man!

Is it fresh video? I recall we addressed that issue for you when hitting high balls with racquet head still below handle?

 

[FiReFTW]

You are speeding up your arm like a man!

Is it fresh video? I recall we addressed that issue for you when hitting high balls with racquet head still below handle?

Its fresh but I have no clue what you just said haha

 

[a12345]

Dunno, I never really went that much into such details, not even sure how I do it

Heres my fh

You have independent arm movement and you are turning at the same time.

You pull your arm through as youre still turning your body forwards, losing all of the effects of the lag.

Turn your body forwards, stop, then pull your arm through at the last minute.

When you turn your body just think about trying to use your turn to stretch your forearm muscles as your arm gets left behind. Your forearm will probably feel tired as it gets stretched and unstretched.

 

[FiReFTW]

You have independent arm movement and you are turning at the same time.

You pull your arm through as youre still turning your body forwards, losing all of the effects of the lag.

Turn your body forwards, stop, then pull your arm through at the last minute.

When you turn your body just think about trying to use your turn to stretch your forearm muscles as your arm gets left behind. Your forearm will probably feel tired as it gets stretched and unstretched.

See its this that I don't agree with, the stop of the body is due to controlling the swingpath and aiming, you don't need to stop your body to release the racquet, it happens when the arm reaches the forward position and starts curving inside the body.

Roger here doesn't stop his body either

Neither does Dimitrov

When the arm gets pulled the racquet lags behind and stretches the forearm muscles and the acceleration forward keeps that stretch, but as the arm curves inwards into the body the forward acceleration starts slowing and the racquet gets released.

 

[a12345]

See its this that I don't agree with, the stop of the body is due to controlling the swingpath and aiming, you don't need to stop your body to release the racquet, it happens when the arm reaches the forward position and starts curving inside the body.

Roger here doesn't stop his body either

Neither does Dimitrov

When the arm gets pulled the racquet lags behind and stretches the forearm muscles and the acceleration forward keeps that stretch, but as the arm curves inwards into the body the forward acceleration starts slowing and the racquet gets released.

He does stop turning. And he stops way before he hits the ball. If you try stop turning and then hit the ball , your momentum of your arm going around your chest after youve hit the ball will still carry you around and you will keep turning, but you yourself actively stopped turning long before that, if that makes sense.

 

[FiReFTW]

He does stop turning. And he stops way before he hits the ball. If you try stop turning and then hit the ball , your momentum of your arm going around your chest after youve hit the ball will still carry you around and you will keep turning, but you yourself actively stopped turning long before that, if that makes sense.

His hips, body and everything keeps turning, just like Dimitrov or Serena or Djokovic before, but even tho it looks the same I guess he stops turning because you say so.

 

[a12345]

His hips, body and everything keeps turning, just like Dimitrov or Serena or Djokovic before, but even tho it looks the same I guess he stops turning because you say so.

Another way to think of it, if I just stand facing straight forwards on one foot and swing hard from right to left across my body using just my arm and nothing else, my body will end up facing to the left but I didnt actively turn my body.

Given that you have independent arm movement, at the very least if you stop turning your body before contact point you will have a stable position from which to hit the shot and you wont over rotate, which itself is a good thing.

 

[FiReFTW]

Another way to think of it, if I just stand facing straight forwards on one foot and swing hard from right to left across my body using just my arm and nothing else, my body will end up facing to the left but I didnt actively turn my body.

Given that you have independent arm movement, at the very least if you stop turning your body before contact point you will have a stable position from which to hit the shot and you wont over rotate, which itself is a good thing.

I do agree I was overrotating a bit here, I tend to do that when I don't watch the ball and look to the other side of the court, when I focus on watching the ball then the head itself puts a bit of a break to the momentum and makes it more stable after hitting.

But I don't really notice any difference between, and im also actively stoping my momentum at times when im late in order to release the lag and get good spin and pace from akward positions, but the only difference I notice is just the timing, the release happens regardless.

 

[FiReFTW]

This video is the best in my opinion

 

[Dragy]

Its fresh but I have no clue what you just said haha

Here are couple of shots:

Now compare to Roger's hitting the ball on similar height:

By the way, this issue may be caused by same issue of forcing torso rotation while making contact, but it looks to me you stop facing target nicely. Then you swing your arm forward, but "overpull" it up and forward, which delays racquet release. This may be just a high ball issue. Just experiment with leaving your arm lower, just a tad below the ball, and releasing/WWing the racquet a tad earlier.

 

[FiReFTW]

Here are couple of shots:

Now compare to Roger's hitting the ball on similar height:

By the way, this issue may be caused by same issue of forcing torso rotation while making contact, but it looks to me you stop facing target nicely. Then you swing your arm forward, but "overpull" it up and forward, which delays racquet release. This may be just a high ball issue. Just experiment with leaving your arm lower, just a tad below the ball, and releasing/WWing the racquet a tad earlier.

Yes probably timing, i do find higher balls much more difficult and ive also not hit much against them.
But im sure i dont always make contact like this but most likely alot of times.
Not sure what effect it has on the ball compared to slightly later timing.

Here is roger he seems to always make it just right tho on one it does seem like hes just a bit late.

 

[ByeByePoly]

What did Curisoity say about the off arm? Forehand?

Curiosity points out tucking off arm is used to break torso/shoulder rotation right around full racquet lag (arm does not lag, racquet does at the hand/wrist). The arm is getting the big momentum pass (and I say arm starts to add momentum) from that full racquet lag at the slot. I don't see the tuck as clearly as he does, and I don't do it in my fh (as far as I know), but this attempt to break/slow shoulder rotation is related to OP's point.

 

[Dragy]

Not sure what effect it has on the ball compared to slightly later timing.

Go find out

For me it makes RH angle control much more natural. Also it helps keeping arm not higher than shoulder line without tilting spine away. Which is stronger range of motion.

 

[Raul_SJ]

@ByeByePoly , Do you see any difference between Serena and Djok, Post 112?

Apparently, Serena is closer to Brian Gordon Type I: "arm and trunk rotating forward together" while Djok is Type III: "independent arm motion from the shoulder joint".

But I don't see much difference.




free picture hosting

 

[FiReFTW]

Go find out

For me it makes RH angle control much more natural. Also it helps keeping arm not higher than shoulder line without tilting spine away. Which is stronger range of motion.

Thinking logically, i would assume the lower the racquet angle the more up the trajectory of the ball.

That would make sense as the lower the ball the more the tip is pointed down.

And the lower the ball the more upward trajectory you need.

That would also make sense since im really imparting heavy spin and net clearance on these balls.

I have a feeling if i would try to hit them more aggressive with a lower clearance that it would be impossible with the tip bellow ball at contact.

Thats exactly what im gonna try next time

 

[ByeByePoly]

@ByeByePoly , Do you see any difference between Serena and Djok, Post 112?

Apparently, Serena is closer to Brian Gordon Type I: "arm and trunk rotating forward together" while Djok is Type III: "independent arm motion from the shoulder joint".

I don't see much difference.

https://imgur.com/63qLHqd

"Do you see any difference between Serena and Djok"

Djokovic is less of a narcissist.

I listened to the Gordon video a long time ago ... don't remember his types. If he is claiming the arm lags the shoulder line in any type, then I don't see it. If he means shoulder rotation forward lags hip rotation forward ... I don't see that either. I see shoulders turned past hips, hips turned past feet ... and everything starting rotating forward at same time. Hips forward rotation completes and shoulders continue on because of shoulder/hip separation (just a fancy way of saying shoulders turned past hips in backswing).

In the pics above comparing Djokovic and Serena ... they look very similar to me. Nothing jumps out as a major difference in FHs to me.

 

[FiReFTW]

Go find out

For me it makes RH angle control much more natural. Also it helps keeping arm not higher than shoulder line without tilting spine away. Which is stronger range of motion.

Heres my low ball for comparison, but its 30fps so blurry

 

[ByeByePoly]

@ByeByePoly , Do you see any difference between Serena and Djok, Post 112?

Apparently, Serena is closer to Brian Gordon Type I: "arm and trunk rotating forward together" while Djok is Type III: "independent arm motion from the shoulder joint".

I don't see much difference.

https://imgur.com/63qLHqd

Oh ... missed your pics showing FH types. Right out of the gate, I bet at contact all three have arms turned forward at shoulder joint (arm moved indedependent of trunk at the end).

Also in all 3 types ... the arm and hand travel with shoulder line (hitting shoulder if one prefers), so I am missing this independent shoulder to arm thing. If he means independent arm rolling (ATP flip), racquet lag ... yes.

Obviously ... when Mr Yandell says:

"The brilliant biomechanical researcher Brian Gordon measured what actually happens."

One would be wise to listen to Mr Gordon and not Mr BBP. In fact, I will take that same advice and try and watch his video again later today. I will post "where I was crazy wrong" after.

 

[tennishabit]

Dunno, I never really went that much into such details, not even sure how I do it

Heres my fh

ur arm take off a bit too early so the torque generated/loaded by leg/waist/torso/shoulder didn't fully transfer/amplify/convert into the rkt head speed. also between all leg/waist/torso/shoulder need each respective 'latency'/'elastic' ie so called kc or 'ssc:?))' whatever u like 2 call it........

all abt timing.....lololololol man.........the charging units went in too early n the multi-stage artillery coverage hasn't finished yet, dat's gonna hurt.................

 

[Dragy]

Thinking logically, i would assume the lower the racquet angle the more up the trajectory of the ball.

That would make sense as the lower the ball the more the tip is pointed down.

And the lower the ball the more upward trajectory you need.

That would also make sense since im really imparting heavy spin and net clearance on these balls.

I have a feeling if i would try to hit them more aggressive with a lower clearance that it would be impossible with the tip bellow ball at contact.

Thats exactly what im gonna try next time

It's related to the arm:

So lower the arm - lower the head, in line with arm, or maybe even lower on extreme cases. Higher than arm on most shots by contact, but again, not that strict. Arm structure, distance to the ball and intention might cause variance. But trailing racquet head below arm line is not typical for ATP guys.

 

[TennisCJC]

It's related to the arm:

So lower the arm - lower the head, in line with arm, or maybe even lower on extreme cases. Higher than arm on most shots by contact, but again, not that strict. Arm structure, distance to the ball and intention might cause variance. But trailing racquet head below arm line is not typical for ATP guys.

I am confused. In the Federer, Nadal and Hass pictures in post #129 (just above), the racket head is trailing the line of the arm. The wrist is slightly laid back at contact in all 3 pictures and if you drew a line extending their arm out beyond contact from their shoulder to the wrist, the racket head would trail that line in every photo. Almost all forehands at ATP and WTA level have a laid back wrist at contact which guarantees the racket head will trail the extended line of the arm.

 

[TennisCJC]

Oh ... missed your pics showing FH types. Right out of the gate, I bet at contact all three have arms turned forward at shoulder joint (arm moved indedependent of trunk at the end).

Also in all 3 types ... the arm and hand travel with shoulder line (hitting shoulder if one prefers), so I am missing this independent shoulder to arm thing. If he means independent arm rolling (ATP flip), racquet lag ... yes.

Obviously ... when Mr Yandell says:

"The brilliant biomechanical researcher Brian Gordon measured what actually happens."

One would be wise to listen to Mr Gordon and not Mr BBP. In fact, I will take that same advice and try and watch his video again later today. I will post "where I was crazy wrong" after.

I will concede the coordination is tight between legs, hips, shoulders, arm, wrist and finally racket head. But, let's think like Yoda for a minute here. The force starts at the ground and flows up and around your core. The energy of the force goes legs, hips, shoulders, arm and finally racket head. The force is continuous and flowing smoothly but the feel is like an energy chain going through legs, hips, shoulders, arm and finally racket head.

Same on a serve. Vic Braden taught coiling the hips and shoulders back away from the court during serve take back and around the time the hitting arm reach parallel to the court with the palm roughly facing downward to start the core and shoulder rotation forward. Vic taught that the core rotation forward would whip the racket head around and through the drop phase and up into contact. You see this in a lot of baseball pitchers too as they will leave the arm back and start the forward and around motion of the coil which pulls the arm forward.

I agree with you that the shoulder to arm thing is "independent" but I do think there a timing issue and shoulder rotation is before arm movement in the chain. I also think you have to be careful how you try to implement this. It should be a smooth energy force following together and if you try to force the arm to lag behind, you could very well screw up your forward.

Try throwing a 3 -5 lb medicine ball starting low with arms extended low and at back hip. to get a good throw, you'll develop a energy force that is legs, hips, shoulders and arms. To the naked eye, it will look like like one motion but it will feel like like energy flowing from the ground up and around your center.

 

[Raul_SJ]

I will concede the coordination is tight between legs, hips, shoulders, arm, wrist and finally racket head. But, let's think like Yoda for a minute here. The force starts at the ground and flows up and around your core. The energy of the force goes legs, hips, shoulders, arm and finally racket head. The force is continuous and flowing smoothly but the feel is like an energy chain going through legs, hips, shoulders, arm and finally racket head.

Is this a subtle thing or can we see actually the difference between Type 1 or 2 forehands vs Type 3? I don't see much difference between Type 1 Serena vs Type 3 Djok.

I know that ATP-style has the flip and compact takeback. But other than that, the Serena vs Djok pics look the same,




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[Dragy]

I am confused. In the Federer, Nadal and Hass pictures in post #129 (just above), the racket head is trailing the line of the arm. The wrist is slightly laid back at contact in all 3 pictures and if you drew a line extending their arm out beyond contact from their shoulder to the wrist, the racket head would trail that line in every photo. Almost all forehands at ATP and WTA level have a laid back wrist at contact which guarantees the racket head will trail the extended line of the arm.

It should be my fault with the wording. I 100% agree with you about laid back wrist. But since @FiReFTW posted his hitting against high ball a tangent discussion rose about height or racquet head at contact against hand/handle. And that's what my pictures refer to: vertical plane.

 

[a12345]

Whilst weve compared different forehand strokes between WTA players and ATP players, what I thought would be good is to look at different forehand strokes by the same player so that we can compare 2 different shots by the same person.

In the first video, albeit its more of a soft warm up, you can see Federer is meeting the ball almost in unison with his shoulder turn. Hes hitting the ball back in much more of a drive through motion like Serena or Halep would. Hes just hitting the ball back across the court without much spin.

In this second video you see a greater separation between the shoulder turn and the arm. And you can see hes hitting a much more "whippy" shot in these second videos. Theres more of a delay between the end of the shoulder turn and the when the racket hits the ball compared to the first video because hes turned his body earlier to stretch the forearm muscles and then releasing them.

Now whilst im not sure how much effort hes making in the 1st video, he is nevertherless hitting 2 different forehands with a differently timed kinetic chain. In the first 1 its much more linked, in the 2nd its much more segmented.

 

[a12345]

Is this a subtle thing or can we see actually the difference between Type 1 or 2 forehands vs Type 3? I don't see much difference between Type 1 Serena vs Type 3 Djok.

I know that ATP-style has the flip and compact takeback. But other than that, the Serena vs Djok pics look the same,




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The issue is with the shot you are using from Djokovic to benchmark against Serena.

This is the original video.

And the first shot he hits does look a bit like Serenas, but hes quite idly hitting the ball back without a whole lot of effort.

If you fast forward to the shot at 1.05 hes now starting to whip the ball a bit more.

Also bear in mind you dont have to whip every ball. Unless your surname is Nadal.

 

[ByeByePoly]

.

I will concede the coordination is tight between legs, hips, shoulders, arm, wrist and finally racket head. But, let's think like Yoda for a minute here. The force starts at the ground and flows up and around your core. The energy of the force goes legs, hips, shoulders, arm and finally racket head. The force is continuous and flowing smoothly but the feel is like an energy chain going through legs, hips, shoulders, arm and finally racket head.

Same on a serve. Vic Braden taught coiling the hips and shoulders back away from the court during serve take back and around the time the hitting arm reach parallel to the court with the palm roughly facing downward to start the core and shoulder rotation forward. Vic taught that the core rotation forward would whip the racket head around and through the drop phase and up into contact. You see this in a lot of baseball pitchers too as they will leave the arm back and start the forward and around motion of the coil which pulls the arm forward.

I agree with you that the shoulder to arm thing is "independent" but I do think there a timing issue and shoulder rotation is before arm movement in the chain. I also think you have to be careful how you try to implement this. It should be a smooth energy force following together and if you try to force the arm to lag behind, you could very well screw up your forward.

Try throwing a 3 -5 lb medicine ball starting low with arms extended low and at back hip. to get a good throw, you'll develop a energy force that is legs, hips, shoulders and arms. To the naked eye, it will look like like one motion but it will feel like like energy flowing from the ground up and around your center.

OR ... there is no k-chain sequence of events below the shoulders ... just one big windup, and one big unwind to turn the shoulders with the arm attached turned as an extension of the hitting shoulder.

Look at first two Djokovic picks above. Think of the arm as a fixed extension of the shoulder line, or if one prefers, the shoulder line a fixed extension of the arm. The arm and hand move together from pic #1 to pic #2 ... this is the opposite of independent. Note ... as I stated above, if you want to call arm rolling for racquet lag at hand, but for this post lets ignore the flip/arm rolling.

So the goal to hit a fh is to turn that shoulder+arm lever together ... upper arm and hand stay inline as a unit (not in independent). That is a simple thing to understand, instead of an arm only swing with no shoulder turn, we end up at a point with our shoulders and hips turned back, with our arm inline with shoulder line. We have lengthened the lever we are swinging ... was just the arm, now we have rotating torso/shoulder plus the length of the arm. That alone should give more speed at the hand at the end of the lever.

What is happening in Djoker's pic #1 to #2 to get that shoulders+arm lever turning. A ground up sequence/flow of events? OR ... everything below fires/starts at same instant for the simple task of starting the forward swing of the shoulders+arm lever. (remember, we are ignoring racquet at this point as an extension of the shoulders+arm lever ... or as an independent lever). I have watched a frickin zillion pro fh videos ... and not once have I seen a leg drive followed by hip rotation followed by core rotation followed by shoulder rotation causing the arm to be left behind and then catch up as it is whipped by stretched tendons snapping back into place. WTF? Seriously ... that is much better writing than the final season of Game of Thrones. What I see every time is everything below the shoulders firing at the same time with the single purpose of starting that shoulders+arm lever swing. I also agree with @rkelley above ... there is no major effort from pic #1 to #2 ... no stretching ... just a nice relaxed arm coming along for the ride. IMO ... the real effort starts at pic #2 ... and it all fires together ... not a flow of events.

Take a good turn ... and then think "hit with that leading shoulder ... then on beat #2 (Djoker pic #2 slot) add rhs with arm firing. To maintain the hand inline with the shoulders from pic #1 to #2 requires arm muscles ... no other way for that hand to travel there. The arm stiffens "enough" to catch a ride with shoulders rotation.

What k-chain? It's a shoulders+arm hammering.

 

[Raul_SJ]

The issue is with the shot you are using from Djokovic to benchmark against Serena.

This is the original video.

And the first shot he hits does look a bit like Serenas, but hes quite idly hitting the ball back without a whole lot of effort.

If you fast forward to the shot at 1.05 hes now starting to whip the ball a bit more.

Also bear in mind you dont have to whip every ball. Unless your surname is Nadal.

You could be right. The first ball is low, and perhaps why there is no pronounced ATP "flip" and lag.

But assuming waist height balls, and given that ATP swing is so compact, it should always be whip-like. By necessity. Even if one is just casually hitting.

 

[Digital Atheist]

"Do you see any difference between Serena and Djok"
[..]
In the pics above comparing Djokovic and Serena ... they look very similar to me. Nothing jumps out as a major difference in FHs to me.

Agree, they are very similar, with the major and supposedly important exception that at first forward movement (ffm) Djokovic, even with his large backswing, still has the racquet in a slightly pronated elbow position (image 1) and as he swings forward his racquet does the flip thing Macci is always talking about (image 2) which helps generate rhs, whereas Serena is already in the laid back supinated position BEFORE ffm (image 1). It's hard to see that from the side view but it is still visible, and it can be confirmed by watching from the rear. The tennis speed blog guy also did research on this.

https://tennisspeedresearch.blogspot.com/2012/05/roadmap-to-hall-of-fame-forehand-part-6.html

 

[Raul_SJ]

Agree, they are very similar, with the major and supposedly important exception that at first forward movement (ffm) Djokovic, even with his large backswing, still has the racquet in a slightly pronated elbow position (image 1) and as he swings forward his racquet does the flip thing Macci is always talking about (image 2) which helps generate rhs, whereas Serena is already in the laid back supinated position BEFORE ffm (image 1). It's hard to see that from the side view but it is still visible, and it can be confirmed by watching from the rear. The tennis speed blog guy also did research on this.

https://tennisspeedresearch.blogspot.com/2012/05/roadmap-to-hall-of-fame-forehand-part-6.html

Agree with Pic#1. The camera angle is misleading. With the WTA-style, the strings never face down on the forward swing. Serena is not "Patting The Dog". She is still taking the raquet behind the back.

However, with Pic#2, Serena and Dkok both look to have significant wrist lag (wrist extension). Is it possible to have significant wrist lag with WTA style?

 

[FiReFTW]

Agree with Pic#1. The camera angle is misleading. With the WTA-style, the strings never face down on the forward swing. Serena is not "Patting The Dog". She is still taking the raquet behind the back.

However, with Pic#2, Serena and Dkok both look to have significant wrist lag (wrist extension). Is it possible to have significant wrist lag with WTA style?

They both get lag (get in the slot) but the women lay the racquet into the lag beforehand, while the guys get into the lag in the last second by accelerating the body.

Check this video its good:

 

[Raul_SJ]

They both get lag (get in the slot) but the women lay the racquet into the lag beforehand, while the guys get into the lag in the last second by accelerating the body.

Yes, the women can get the wrist lag.
OP refers to two things: 1) lag and 2) snap.
So apparently, the WTA style is only missing the snap/whip of the arm -- it is more of arm and trunk moving together.
ATP style, according to Brian Gordon, is a "multi-segmented swing with aggressive independent arm action".

Some people have a hard time getting that lag and snap/liquid whip motion on their strokes.
And the reason why in my opinion is that they are continuing through their strokes in the classic , smooth, WTA forehand style manner.
The key to feeling and getting the liquid whip happening is understanding that you need to stop turning , and you need to do it abruptly.

 

[a12345]

The difference in rhythm of the body turn in my super technical analysis would be this.

The womens would be Zzzzzzzoom, Zzzzzzzoom, or Whhhhhhhoosh.

The mens would be 1,2 1,2 1,2. with 1 being the body 2 being the arm.

 

[ByeByePoly]

Your body rotation isn't even blowing your skirt up

Edit

The counter to the video above is Keys ... doesn't look wristy ... and yet beats the cr@p out of the ball:

Also no big lag release, no independent arm travel to contact.

 

[FiReFTW]

Your body rotation isn't even blowing your skirt up

Edit

The counter to the video above is Keys ... doesn't look wristy ... and yet beats the cr@p out of the ball:

Also no big lag release, no independent arm travel to contact.

Keys beats the crap out of the ball, but her ball is very flat.
ATP shots are a whole different animal and have much more action on the ball.

 

[ByeByePoly]

Keys beats the crap out of the ball, but her ball is very flat.
ATP shots are a whole different animal and have much more action on the ball.

Yes, Keys hits flat, but it's not like if she adds some topspin it turns into a 3.5 league rally ball.

But that was not the point of my post. The first video (coach Steve) was related to OP:

"Some people have a hard time getting that lag and snap/liquid whip motion on their strokes."

He was focused on body rotation ending, and passing momentum to arm, which I agree with ... but pointing out the biggest LIQUID part probably happens at the wrist. The wrist tends to be key in many sports where the best make it look effortless.

Keys was a bit OT ... but offered a counter to the fist video claim that you couldn't create much power without the loose action at the wrist. To me, I see neither big lag or lag release at the wrist with Key's FH ... and yet she still hits big RHS. That might make the case in our over analysis (deep dive) into everything pro FH rhs ... the biggest contributor might just be the hand moves faster at the end of the arm because of boring centrifugal force. How boring would that be ... and how silly would we all look?

Note: Also posted the first video because I continue to think our body rotation isn't nearly the contributor to rhs that we think. @ChaelAZ said he would use his video skills for me to remove the arm and racquet from full speed FHs ... so we could just watch the body rotation without the racquet. Have you seen the one video where they removed the racquet from a Fed FH video, so you could just watch the hand path. It made a big difference not including the racquet head path in the video. My point ... if I have one ... I think the shoulder rotation handoff ot the arm is a power move, not accumulated speed. I think we power from around the slot ... we stiffen and fire arm muscles into contact ... and hand speed ends up being "plenty fast" (technical tennis term ) by contact. This all seems pretty clear to me watching Keys.... that is a power move getting the shoulders/arm and racquet moving ... not slung rope from hips, torso synchronized swimming. Arm and racquet ... 10 lbs.. ish ... light bowling ball. How do you sling a light bowling ball. So I continue to see the arm stiffen up to catch a ride with the initial shoulder turn forward, and then do it's EXTRA thing going into contact to really ramp up the RHS. With Fed ... it's easy to see his late "jumping on it with his arm" ... but not as clear to me where exactly Keys starts (the moment of shoulder rotation forward ... or also slight delay. It must be slight delay ... because that is how you get smooth power).

fyi ... another way to check @a12345 ATP vs WTA FH body rotation differences is to grab snapshots of hand positions relative to shoulder line at contact. I was going to, but decided it wasn't worth it to me. But a quick check of Keys and Halep at contact shows the hand still in line with shoulder line at contact on their FHs. Check Fed .... and most ATP pros, and there hand is way forward of shoulder line by contact. Not sure that makes for categories of FHs though ... probably find a range/spectrum of contact positions rather than WTA is this, and ATP is that.

btw ... if I hit the ball on my FH as far out in front as you do, I would have to upgrade my glasses prescription. Would not work for me ... need to work closer to home base.