1hbh parametric acceleration
- Thread starter Dou
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Deleted member 23235
Guest
but i'm trying to understand where the parmesan fits into all this
so a vid will help.
rogerroger917
Hall of Fame
He plays golf and comes here to harass troll us.
just look at the 2:00 mark... and try it yourself - actually I had just had a hit and made some adjustment based on what he was saying.
because the racket travels much faster now, you are gonna feel like you hit it much later, almost like slinging this ball from your left pocket area into the right fence.... and that ball is heavy!
rogerroger917
Hall of Fame
SuperSpinner
Semi-Pro
pulling forcefully is going to lead to inconsistency.
why.
this is my thread and we already agreed that you and i have nothing more to talk about.
rogerroger917
Hall of Fame
JohnYandell
Hall of Fame
And lazy equals lazy. Means not does not play. Cannot show anything. Truly nothing more to talk about!
I put in 3 hours a day to put the theories into practice.... and people can't put in 15 minutes just to see what the ball flies like when you pull LEFT on the fh and RIGHt on the bh?
if you tried and the ball doesn't get heavy, then I can tell you what you are doing wrong.... looking at my vid won't help... I am showing you pro's vids, and if those don't help you, you need additional help to make it right.
if you tried and the ball doesn't get heavy, then I can tell you what you are doing wrong.... looking at my vid won't help... I am showing you pro's vids, and if those don't help you, you need additional help to make it right.
Fxanimator1
Hall of Fame
rogerroger917
Hall of Fame
ok you made me laugh.
rogerroger917
Hall of Fame
meant pros' vids I provided.
I do.. and actually am not too far from NY.... if I am in the area will reach out.
rogerroger917
Hall of Fame
I want dou on my doubles team.
down in Joyzee.
D
Deleted member 23235
Guest
haha, so is @rogerroger917
@ptuanminh is jersey city this weekend...
let's get some parametric dubs going!
rogerroger917
Hall of Fame
Parmesan cheese doubles.
Chas Tennis
G.O.A.T.
Bigservesofthands post from 2016 with a quote and reference link to the golf Miura publication. (Quote punctuations missing.)
Thread
https://tt.tennis-warehouse.com/ind...vesofthands-first-serve.563286/#post-10308990
Note - Some of Bigservesofthand's serving techniques do not employ ISR
It was found that, for amass rotating around a pivot, if the pivot is moved in the direction opposite to the direction of centrifugal force of the mass, the kinetic energy of the mass could be increased.The increase is a result of the mutual action of the two governing factors of the system, which are the centripetal force and the pull velocity. A special type of equation of motion governs this phenomenon. second_derivative(theta) + epsilon sin(theta) = 0, and the parameter in the second term of the left-hand side of the equation epsilon characterizes its behavior.
https://www.researchgate.net/public..._inward_pull_of_the_golf_club_at_impact_stage
In the case of the the tennis serve during approach to contact in both traditional and my low bouncing serve, the tennis racquet
is rotating a transversely and along the polar axis around the grip pivot towards the tennis ball. Pull on the grip pivot (which is close to the butt cap in my serve and I assume is pretty close to that for other servers) in the direction opposite to centrifugal force of mass (somewhere towards the top left of the opponents court to around the net maybe - hard to tell exactly it happens so fast) will cause this acceleration.
Thread
https://tt.tennis-warehouse.com/ind...vesofthands-first-serve.563286/#post-10308990
Note - Some of Bigservesofthand's serving techniques do not employ ISR
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Chas Tennis
G.O.A.T.
The article that caused the buzz in golf in 2011. I just noticed that the paper was published in 2001. We are 17 years behind the science! This must have been explored in tennis, even the original publication indicates tennis as an application.
Parametric acceleration - the effect of inward pull
of the golf club at impact stage
K. Miura
http://people.stfx.ca/smackenz/courses/DirectedStudy/Articles/Miura 2001 Parametric acceleration effect of inward pull.pdf
Quote from the conclusion
"Application of this theory to the golf swing revealed
that the clubhead velocity could be increased by the
inward pull motion of the club at the impact stage,
during which no other means of acceleration are
available."
Interpretation of what is meant in golf & What does the golf term 'release' mean? -
"at the impact stage, during which no other means of acceleration are available" - For golf does this mean that the hands are no longer accelerating the club head in the forward direction as when the swing began, they are freely drifting except for any parametric acceleration from radial pull? But the hands may still have the radial force approximately perpendicular to the main club head trajectory?
Is this what the term 'release' means for golf - that the hands are no longer supplying forward force?
Parametric acceleration - the effect of inward pull
of the golf club at impact stage
K. Miura
http://people.stfx.ca/smackenz/courses/DirectedStudy/Articles/Miura 2001 Parametric acceleration effect of inward pull.pdf
Quote from the conclusion
"Application of this theory to the golf swing revealed
that the clubhead velocity could be increased by the
inward pull motion of the club at the impact stage,
during which no other means of acceleration are
available."
Interpretation of what is meant in golf & What does the golf term 'release' mean? -
"at the impact stage, during which no other means of acceleration are available" - For golf does this mean that the hands are no longer accelerating the club head in the forward direction as when the swing began, they are freely drifting except for any parametric acceleration from radial pull? But the hands may still have the radial force approximately perpendicular to the main club head trajectory?
Is this what the term 'release' means for golf - that the hands are no longer supplying forward force?
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rogerroger917
Hall of Fame
If only Bssh and greg diamond can get together and with the help of dou coach someone like Kyrgios. Imagine the science!
ok you guys enjoy.... have to work this weekend.. unlike some people who just talk tennis, I actually have to run 2 businesses besides hitting balls 3 hours a day.
Fxanimator1
Hall of Fame
you people study up... our resident researcher is finding good stuff.
I actually am ok if anyone wants to video when we meet up for a hit... I just don't want to bother, and I think it's pointless - if you have to see uncle Toni's own hitting video before you get advice from him, I am sure you will lose out. (not saying I am uncle Toni)..
and of course you'd never ask a surgeon to operate on your tumor only if he shows he'd had cancer himself.
and of course you'd never ask a surgeon to operate on your tumor only if he shows he'd had cancer himself.
rogerroger917
Hall of Fame
Chas Tennis
G.O.A.T.
Golf swing showing shoulder position vs club position for parametric acceleration. Only before impact adds to club head speed.
Weather this weekend is crazzzzy
this is a fail without Jesse
will do if in the area.. thx...
actually about 10 years ago I worked in that area and used to hit with a few guys in that 'bubble' near the USTA
just went out for a hit... and that latest oscar video helped quite a bit.... with this method I used to hit too flat, so buy starting the hand a little lower the curvatures are back.
the back hand is actually easier because there is already so much spin.. just rip the sucker towards the right fence ( not the direction of the follow thru, but the direction of the swing! ).... that ball is incredibly heavy.
the back hand is actually easier because there is already so much spin.. just rip the sucker towards the right fence ( not the direction of the follow thru, but the direction of the swing! ).... that ball is incredibly heavy.
Release is the release of clubhead lag. Generally it describes the clubhead moving from behind the hands to ahead of them. A more accurate description would be the angle between the shaft and the lead forearm increasing to 180* or more. The later you delay release, the better.
Chas Tennis
G.O.A.T.
Do the strong hand forces reduce/disappear at some point before impact and then the already achieved club head velocity drifts to impact? In other words, Force =mass x acceleration up until a short distance before impact and then F= 0 or small and the club head velocity does not change (or change much). Or does F=ma continue through impact and F is significant?
Here is the graph (from Miura's publication in post #174 above) that seems to imply the hand forces have decreased for the BASE golf stroke. I interpret the BASE graph to be the golf swing without parametric acceleration (PULL).
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There is a lot of disagreement in the golf world over this entire issue. Golf instruction has typically been even worse than tennis instruction. Two things changed it in the past 20 odd years. One, the rise of Tiger Woods, who was kind of a Federer figure in terms of influencing technique. Two, the availability of high speed video, which proved that many accepted precepts were in fact wrong.
The role of the hands and wrists at impact is at least as confusing as in the serve or modern FH. I would day the accepted wisdom now is that they play a largely passive role and any attempt to gain clubhead speed through their manipulation will result in a lack of control and consistency. That said, there clearly is movement in them through impact, as the lead wrist supinates and bows and the trail wrist goes from extension into at least a neutral position. Interestingly, the Iron Byron hitting machine, which is often used by manufacturers to test equipment, has a completely passive "wrist" hinge. It's a two lever system but only the upper lever is powered. Obviously parametric acceleration plays a big role.
It is generally thought that clubhead speed increases through the impact zone and, if no ball is present, will reach max speed past the impact position. If you watch long drive competitors, they generally tee the ball much further forward in their stance than Tour players. Partly this is the result of trying to achieve maximum upward angle of attack at impact, which minimizes spin, but I believe it also is an attempt to achieve max clubhead speed at impact. Tour players have to balance distance and control. In long drive, distance is the goal.
A key distinction between elite players and hackers is the degree of lag held into impact. There is a strong correlation between the club to forearm angle when the hands pass the rear leg coming down and clubhead velocity. Since elite players have relatively passive hands at impact, this tells me parametric acceleration is playing a big role.
In my opinion, the short answer to your question is that there is a considerable F acting on the club at impact but that it is largely parametric in nature. There is some additional force provided by trail arm ISR .
tennisbike
Professional
Ok, parametric acceleration! Interesting that in 2016 I wrote an email asking Andy Fitzell about parametric acceleration. Mr. Fitzell makes some very nice video.
I started messing around nunchucks trying to understand tennis stroke a couple of years back. Knowing how to whip nunchucks enable me to whip a tennis racket with 2 fingers. Yes, the racket can come around very quick with very little effort, if you pull it just right.
My understanding is that some form of parametric acceleration probably exist in all forms of tennis swing. If it is not used then everyone will be manipulating the tennis racket as if it is one rigid unit from the racket all the way to the shoulder. Yes, that is kind of a visual model I get when I read Vic Braden's books, keeping wrist firm, swing the racket from the shoulder. I get it, keeping everything in relatively fixed angle and you keep things simple and be more consistent. But in reality, everything flexes. Parametric acceleration is in even in waiter's serve. It is everywhere, like hammering a nail.
How is a hammer used? You start holding it straight up, lift up straight right directly above the nail. Then drop the hammer head straight down as the hand goes down and hand/handle back away. How about the pick? same thing.
If we can agree on this, some PA, is at play during most swinging motion, then we can discuss how to harness it.
Well not exactly, if understanding the optimum motion path which enable us to program ourselves then great. The biggest problem is instruction and human body is not so easy to program. Well, let's go back, we actually do not know exactly what motion is optimum. And then what is optimum. What is good for max speed is not necessarily good for control, as the previous post nicely pointed out.
As someone who teaches physics in high school, I want to point out that, the end result is actually the speed we want. We actually want a high racket head speed moving translationally at contact, because we want control and not a slap. You can have a small acceleration for longer time or large acceleration and shorter time, both can achieve a high speed. It is a wonderful world, we do not all have to do it the same way.
My thought at this point is... focus on the swing of the racket, not your body. Feel the swing, play around with it. Most of all have fun!
I started messing around nunchucks trying to understand tennis stroke a couple of years back. Knowing how to whip nunchucks enable me to whip a tennis racket with 2 fingers. Yes, the racket can come around very quick with very little effort, if you pull it just right.
My understanding is that some form of parametric acceleration probably exist in all forms of tennis swing. If it is not used then everyone will be manipulating the tennis racket as if it is one rigid unit from the racket all the way to the shoulder. Yes, that is kind of a visual model I get when I read Vic Braden's books, keeping wrist firm, swing the racket from the shoulder. I get it, keeping everything in relatively fixed angle and you keep things simple and be more consistent. But in reality, everything flexes. Parametric acceleration is in even in waiter's serve. It is everywhere, like hammering a nail.
How is a hammer used? You start holding it straight up, lift up straight right directly above the nail. Then drop the hammer head straight down as the hand goes down and hand/handle back away. How about the pick? same thing.
If we can agree on this, some PA, is at play during most swinging motion, then we can discuss how to harness it.
Well not exactly, if understanding the optimum motion path which enable us to program ourselves then great. The biggest problem is instruction and human body is not so easy to program. Well, let's go back, we actually do not know exactly what motion is optimum. And then what is optimum. What is good for max speed is not necessarily good for control, as the previous post nicely pointed out.
As someone who teaches physics in high school, I want to point out that, the end result is actually the speed we want. We actually want a high racket head speed moving translationally at contact, because we want control and not a slap. You can have a small acceleration for longer time or large acceleration and shorter time, both can achieve a high speed. It is a wonderful world, we do not all have to do it the same way.
My thought at this point is... focus on the swing of the racket, not your body. Feel the swing, play around with it. Most of all have fun!
I think significant PA needs to be taught and learned... pulling across/backwards is counter-intuitive as it's going away from the target.
tennisbike
Professional
The word need is a little strong. There are generally more ways to accomplish any one thing. But ok..
I agree it is counter intuitive. It kind of depends on your racket path. If you like my hammer analogy, you can drag/pull the racket first toward the impact point and then pull toward the center, or say left if you are right handed. But the acceleration actually just started to come on as the racket is turning to face the target. If you look at the nunchuck analogy, when you snap the stick forward and pull 90 degree, the stick will whip and hit the target from the side. So for tennis, we have to turn 90 degrees. The stick need to kind of move not opposite to the ball but at an angle, then by moving toward the front, you will have created PA.
For backhand, my feeling is that it is difficult to manipulate upper arm quickly. I get the feeling this change of direction comes from external shoulder rotation, kind of reverse of the pronation in service motion. I know it can be done. But I do not focus on this when I practice now a days. The whip was part of my exploration though. Have fun! Use just 2 fingers to whip the racket!
I agree it is counter intuitive. It kind of depends on your racket path. If you like my hammer analogy, you can drag/pull the racket first toward the impact point and then pull toward the center, or say left if you are right handed. But the acceleration actually just started to come on as the racket is turning to face the target. If you look at the nunchuck analogy, when you snap the stick forward and pull 90 degree, the stick will whip and hit the target from the side. So for tennis, we have to turn 90 degrees. The stick need to kind of move not opposite to the ball but at an angle, then by moving toward the front, you will have created PA.
For backhand, my feeling is that it is difficult to manipulate upper arm quickly. I get the feeling this change of direction comes from external shoulder rotation, kind of reverse of the pronation in service motion. I know it can be done. But I do not focus on this when I practice now a days. The whip was part of my exploration though. Have fun! Use just 2 fingers to whip the racket!
Chas Tennis
G.O.A.T.
Rather than pulling the upper arm in some way with timing, there may be other ways to have the shoulder pull back somewhere before the racket impacts the ball. If your timing is off you get less of a speed increase. Later than optimal you may lose pace but earlier pace may be the same. ?
If you look at Wawrinka's backhand in videos his shoulder is moved forward on his body early and winds up back later in the stroke. Wouldn't he get the same pace increase early or late if before impact? I have not observed the timing relative to impact but it would seem that when the rotation axis is around the shoulder joint having the shoulder move back simply as part of the uppermost body turn could serve as a pull. ?
An additional interesting subject is that the one hand backhand technique that uses the uppermost body turn for initial forward acceleration and then is followed by the shoulder joint before impact has an automatic radius change. That change in radius occurs when the uppermost body turn slows and the shoulder joint moves the upper arm away from the chest. The first rotation axis is the center of the body, neck area maybe, and then the axis switches to the shoulder joint. The radius gets longer. Does that radius change have the same effect as a parametric acceleration pull? ? In golf they seem to use the shoulder rise cause by several body motions, leg straightens, shoulder, shoulder girdle turn, move up on body, etc.
It is true that parametric acceleration is in many places and often occurs. But if we don't understand it for tennis strokes we would not be able to manipulate the stroke for pace or control.
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Chas Tennis
G.O.A.T.
Look at the backhand at 1:21 around impact. The arm and shoulder motion could be for an adjustment of racket face position or parametric acceleration. ?
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to me his body language is saying pulling towards the back fence.
Hmgraphite1
Hall of Fame
Definitely gotta stop the shoulder rotation momentarily to all the momentum into the shot
Hmgraphite1
Hall of Fame
Its good to build a resume of memories of things to try/ consider, depends on capacity
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