Stroke analysis - Adelina 11 years old

[jeffreycounts]

That makes a lot of sense. So the only question i have left would be what affect does the ssc from the forearm muscles have? Looking at it again perhaps it helps propels the arm forward?

I'm asking based on the below quote:

"The dynamic slot creates a turbocharging effect because it brings elements of the stretch-shorten cycle into play in the shoulder muscles, and to a less important extent, in forearm muscles as well"

[seano]

Wouldn't the amount of elbow bend at contact determine forearm involvement?

[BrianGordon]

Sean is 2 for 2 - nice work.

Forearm SSC would not act to propel the arm forward. It would enhance pronation in more bent arm configurations. In these configurations there is not a direct link between the racquet rotation in the flip and shoulder external rotation (as with the straight arm). Rather ESR is a function of forearm inertia and indirectly the flip supinating the forearm. This can produce a SSC enhancement to pronation which acts independently (of ESR) to produce vertical racquet speed (proportional to the degree of bend) in bent arm forehands.

[stroke]

My point was not that the wrist position was great, but that for an eight year old to create the stretch shortening cycle, as opposed to laying the wrist back from the beginning, this was probably a natural way for her to do it. And then I pointed out that players like Murray, Khachanov, Tiafoe, etc do it on their forehands, so it clearly serves some purpose in initiating the stroke. When I say "dynamic pull" I just mean creating the stretch shortening cycle where the wrist goes from a neutral position to a laid back position in a quick burst. And that's what I do see her doing, which i thought was nice, even if it's not in the most ideal manner. I mean none of the forehands below are pretty that's for sure. I'm not advocating for it. But I think there is probably a reason all these players naturally do this, one being to create the stretch shortening cycle.

wrist.jpg

Jeff, looking at that still shot of Tiafoe, he seems to have a neutral wrist, even though the racquet head is below his hand. I always thought, I guess because of that racquet head position, that he had a flexion/bent down wrist position as Khachanov clearly does. Tiafoe and Murray obviously have a significantly different set up position even though their wrist position seem similar.

[jeffreycounts]

Jeff, looking at that still shot of Tiafoe, he seems to have a neutral wrist, even though the racquet head is below his hand. I always thought, I guess because of that racquet head position, that he had a flexion/bent down wrist position as Khachanov clearly does. Tiafoe and Murray obviously have a significantly different set up position eleven though their wrist position seem similar.

Murray looks possibly neutral as well. Nothing like Khachanov.

[jeffreycounts]

So... while the racquet rotates via the centripetal force (allowed by wrist flexion),.

Brian/Seano - So a player needs to "allow" the wrist flexion to happen in order to get the racket to rotate around with centripetal force.. In order for it to happen it sounds like you would have to release the wrist a bit to get this to happen, otherwise the racket wouldn't rotate around. Is that accurate? It does need to be released or relaxed, otherwise you would be stuck at 90 degrees. If I lay my wrist back 90 degrees i feel my forearm muscles engaged. If I relax my forearm muscles then the wrist seems to flex naturally.

[10splayer]

Im wondering if the angle (90 degrees or less or not) at impact has more to do with racquet orientation and the subsequent shot line then for a power release. It seem that on down the line and inside out forehands there is more of a 90 degree angle, as we know the face angle at impact is the most consequential determinant in direction

[seano]

Here's a great video of Brian explaining the ATP Type 3 forehand. At around the 39.00 minute mark, he explains how the centripetal force works.

https://www.youtube.com/watch?v=o2Cqwa5bxV0&t=1326s

[jeffreycounts]

Here's a great video of Brian explaining the ATP Type 3 forehand. At around the 39.00 minute mark, he explains how the centripetal force works.

https://www.youtube.com/watch?v=o2Cqwa5bxV0&t=1326s

Very helpful! Thanks Seano.

It was very quick but I heard Brian say that because the arm is attached to the shoulder it “has to start breaking” in the latter part of the pull as the pull starts to come inward. At that point if you allow it, centripetal force will whip the racket around “like a rusty gate”. I thought something had to slow down in order for the racket to come around, And apparently it’s because the pull starts to come inward combined with the shoulder joint that you will get this centripetal force. This seems to be like hitting the breaks in your car at speed and then things will come flying forward. But in this case the breaking isn’t deliberate but a consequence of the pull and the shoulder. And instead of coming forward like in the car, the racket comes around.

[stroke]

Very helpful! Thanks Seano.

It was very quick but I heard Brian say that because the arm is attached to the shoulder it “has to start breaking” in the latter part of the pull. At that point if you allow it, centripetal force will whip the racket around “like a rusty gate”. I thought something had to slow down in order for the racket to come around, And apparently it’s because the pull starts to come inward combined with the shoulder joint that you will get this centripetal force. This seems to be like hitting the breaks in your car at speed and then things will come flying forward. But in this case the breaking isn’t deliberate but a consequence of the pull and the shoulder. And instead of coming forward like in the car, the racket comes around.

I think one key might be as BG used to point out, the model type 3 with the "independent arm action", is what separates the model Nadal Fed type 3 from a lot of the other forehands. This is tied in to me with Jeff's hitting the breaks on the car analogy.

[seano]

I use this analog to explain centripetal force. A boat pulling a skier behind it and when the driver turns sharply, the skier will whip around quickly. That's centripetal force.

[jeffreycounts]

I use this analog to explain centripetal force. A boat pulling a skier behind it and when the driver turns sharply, the skier will whip around quickly. That's centripetal force.

And in this case, instead of turning the boat, it’s the shoulder joint that starts the redirection.

[seano]

As the hand pulls forward, because it is attached to the shoulder, it starts to break to the inside "the hand will start to pull to the inside which creates a force at the butt end of the racquet that makes the racquet rotate into contact" (centripetal force), explanation around the 39:40 mark of the video. This occurs after the linear hand path and the dynamic slot.

[BrianGordon]

Jeff - Yes, the wrist must allow the centripetal force to rotate the racquet. I think of it as a variably resisted hinge in the late stages of the forward swing.

10s - Yes, this was the point I made (not very clearly) in "post 14". The racquet rotation will add to racquet head speed forward but the main goal is proper alignment as a determinant of shot direction.

Florin - I chimed in here to point out that in my experience you want to address the orientation of the racquet (primarily a wrist function) at the end of the back swing. The reason I chimed in is because I admire you for trying to construct the forehand this way (despite common resistance). I thought my successes and failures might be of assistance. I fear our theoretical deviation (while applicable) has detracted from focus on your daughter's stroke. If so, sorry - back to Adelina and keep up the great work!

[don_budge]

Im wondering if the angle (90 degrees or less or not) at impact has more to do with racquet orientation and the subsequent shot line then for a power release. It seem that on down the line and inside out forehands there is more of a 90 degree angle, as we know the face angle at impact is the most consequential determinant in direction

10s - Yes, this was the point I made (not very clearly) in "post 14". The racquet rotation will add to racquet head speed forward but the main goal is proper alignment as a determinant of shot direction.

Florin - I chimed in here to point out that in my experience you want to address the orientation of the racquet (primarily a wrist function) at the end of the back swing. The reason I chimed in is because I admire you for trying to construct the forehand this way (despite common resistance). I thought my successes and failures might be of assistance. I fear our theoretical deviation (while applicable) has detracted from focus on your daughter's stroke. If so, sorry - back to Adelina and keep up the great work!

Its about as good as theoretical deviation's get. Plus isn't it great to hear from good old 10splayer! I remember when this forum was great. MFGA! Make the Forum Great Again. But Dr. Gordon...lost in this discussion was an interesting point that florin brought up on the first page that for some reason I am no longer able to access. He questioned whether the racquet was to big for his slender eleven year old daughter. I also found that it appeared that it seemed to be a bit unwieldy for her and recommended upping her physical training. Could the raquet be too heavy for her to get that wrist in the position you desire? I know that isn't very technical...but I wonder if it might just be applicable.