dschultz6072
New
Art, if you want LD people (including the current Open Div Champ) to test, PM me.
What Kind of Release is this? & Can an effective swing include no deceleration?
- Thread starter Brian Manzella
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What a great question JD! The evidence I've looked at (which is limited, I am by no means obsessed by the science and the studies like some) suggests that the maximum speeds are the deciding factors, so a higher pelvis rotational speed in the downswing would be desirable. But is there anyone out there with the data and the expertise to prove it? I doubt it.
mandrin
New
Increasingly graphs are being shown re to position, velocity and acceleration. Especially when velocity graphs are shown but discussion is primarily about accelerations, I wonder if this is not a source of confusion for some not quite familiar with the subtle features of these parameters.
I have tried to show, in a very simple way, some characteristics of the data acquisition of position with velocity and acceleration being derived quantities.
Some elementary considerations re acquiring data
I have tried to show, in a very simple way, some characteristics of the data acquisition of position with velocity and acceleration being derived quantities.
Some elementary considerations re acquiring data
Does this help:
VELOCITY -
Suppose a car leaves Chicago and travels for 4 hours with an average speed of 50 miles/hour. Where will it be at the end of this time?
Who knows? The car could be 200 miles (= 50 mi/hr x 4 hr) north of Chicago, it could be 200 miles west - or any other direction. It could even be back in Chicago (if it went 2 hours west, then 2 hours east, for instance)! It could be anywhere within a 200 mile radius of Chicago. That is not a very precise description of the car's motion!
Clearly, speed is not adequate to describe the motion of an object. You need to know its speed and direction.
Velocity is the kinematics concept that describes an objects speed and its direction.
(a) Change in Velocity -
It is important that you be able to recognize when the velocity of an object is changing. Since velocity is speed and direction, the velocity of an object changes if:
it speeds up.
it slows down.
it changes direction.
Note that the velocity of an object can change, even if its speed remains constant. For instance, when a car is going around a curve (like an entrance ramp on an interstate), it is accelerating - even if the speed of the car stays the same. Velocity changes when either speed or direction changes.
ACCELERATION -
Acceleration is the rate at which velocity changes. In other words, knowing the acceleration of an object tells you how fast the velocity of the object is changing.
Since velocity is the rate at which position changes, and acceleration is the rate at which velocity changes, acceleration is a "rate of a rate".
students often get the misconception that "acceleration is a change in velocity". NO!! Acceleration is the rate at which the velocity changes - there's an important difference!
To say that "acceleration is a change in velocity" is like saying "velocity is a change in position" (This does sound silly, doesn't it?). Velocity tells you how fast position is changing. Acceleration tells you how fast velocity is changing.
Acceleration is not a change in velocity (it's the RATE that velocity changes).
It is very important to notice that acceleration is defined in terms of a change in velocity - not speed.
VELOCITY -
Suppose a car leaves Chicago and travels for 4 hours with an average speed of 50 miles/hour. Where will it be at the end of this time?
Who knows? The car could be 200 miles (= 50 mi/hr x 4 hr) north of Chicago, it could be 200 miles west - or any other direction. It could even be back in Chicago (if it went 2 hours west, then 2 hours east, for instance)! It could be anywhere within a 200 mile radius of Chicago. That is not a very precise description of the car's motion!
Clearly, speed is not adequate to describe the motion of an object. You need to know its speed and direction.
Velocity is the kinematics concept that describes an objects speed and its direction.
(a) Change in Velocity -
It is important that you be able to recognize when the velocity of an object is changing. Since velocity is speed and direction, the velocity of an object changes if:
it speeds up.
it slows down.
it changes direction.
Note that the velocity of an object can change, even if its speed remains constant. For instance, when a car is going around a curve (like an entrance ramp on an interstate), it is accelerating - even if the speed of the car stays the same. Velocity changes when either speed or direction changes.
ACCELERATION -
Acceleration is the rate at which velocity changes. In other words, knowing the acceleration of an object tells you how fast the velocity of the object is changing.
Since velocity is the rate at which position changes, and acceleration is the rate at which velocity changes, acceleration is a "rate of a rate".
students often get the misconception that "acceleration is a change in velocity". NO!! Acceleration is the rate at which the velocity changes - there's an important difference!
To say that "acceleration is a change in velocity" is like saying "velocity is a change in position" (This does sound silly, doesn't it?). Velocity tells you how fast position is changing. Acceleration tells you how fast velocity is changing.
Acceleration is not a change in velocity (it's the RATE that velocity changes).
It is very important to notice that acceleration is defined in terms of a change in velocity - not speed.
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ZAP
New
I was kind of reading back through some of the stuff and wondering if we were all thinking the same thing. Even a decreased acceleration is still an acceleration which is still an increase in speed. It looks to me that the graphs and stuff are showing a decrease in angular velocity which would basically mean a decrease in speed in my eyes. I am thinking I am going to need to read through this again.
Brian Manzella
Administrator
Thanks for the education gents. When looking at the kinematic sequence I see the drop off pre-impact of pelvis rotational velocity... so continuing at that point to rotate the pelvis open in the same direction at the same or increasing speed is bad and not what good players are doing. That right?
I still have a question, perhaps not appropriate for this thread, but it still remains about max pelvis speed and dynamic stability. Can you increase max pelvis speed and not upset dynamic stability? A worthwhile pursuit?
Here are my 3D #s to look at for kicks:
12 sensor 3D from 3/2012 - 5 iron:
Peak Speed d/s: 420 (pelvis), 606 (thorax), 716 (arm), 1943 (club)
K-Vest 3 Sensor from 9/2012 when I was playing the best I have played to date:
Peak Speed d/s: 402 (pelvis), 616 (thorax), 1533 (grip/shaft - the sensor is on the back of the lead hand)
The 9/12 session on K-Vest I lit up the swing summary. I of course have issues (spine rotation graph) and little X factor stretch, but you can play some good golf from what I was doing in September. Just curious to hear Brian, Art and others thoughts on trying to increase your peak pelvis speed.
I still have a question, perhaps not appropriate for this thread, but it still remains about max pelvis speed and dynamic stability. Can you increase max pelvis speed and not upset dynamic stability? A worthwhile pursuit?
Here are my 3D #s to look at for kicks:
12 sensor 3D from 3/2012 - 5 iron:
Peak Speed d/s: 420 (pelvis), 606 (thorax), 716 (arm), 1943 (club)
K-Vest 3 Sensor from 9/2012 when I was playing the best I have played to date:
Peak Speed d/s: 402 (pelvis), 616 (thorax), 1533 (grip/shaft - the sensor is on the back of the lead hand)
The 9/12 session on K-Vest I lit up the swing summary. I of course have issues (spine rotation graph) and little X factor stretch, but you can play some good golf from what I was doing in September. Just curious to hear Brian, Art and others thoughts on trying to increase your peak pelvis speed.
It appears that there is still the mis-perception that the deceleration(s) is/are intentional in the kinematic sequence.
Matt Bryda
New
What if it was based on some other major thing taking place during the downswing..
Thinking out loud
Deechpga2288
New
Keeping to the theme of WHAT.
THe Pelvis HAS to decelerate in a powerfl golf swing BECASUE the forces being applied above it force it to slow down. If a pelvis does not decelerate (and yes this is possible) the gol swing will be weak and lack power production.
A cool test would be to show this....
Sit in a rotating chair, hold a golf club out in front of your chest and as hard and fast as you can, rotate one way. When you do this, your lower half in the chair shoots the opposite way. Now when ancored to the ground this can not happen but, it certainly will apply some brakes!!!
THe Pelvis HAS to decelerate in a powerfl golf swing BECASUE the forces being applied above it force it to slow down. If a pelvis does not decelerate (and yes this is possible) the gol swing will be weak and lack power production.
A cool test would be to show this....
Sit in a rotating chair, hold a golf club out in front of your chest and as hard and fast as you can, rotate one way. When you do this, your lower half in the chair shoots the opposite way. Now when ancored to the ground this can not happen but, it certainly will apply some brakes!!!
Deechpga2288
New
I probably should have read Art's post before I responded. Sorry fr the duplication guys!
Brian Manzella
Administrator
It can be taught.
Absolutely.
It can be attempted to be taught and have the golfer ruined afterward.
You can teach impact to a golfer, do a failed job, and ruin a golfer as well.
Everyone needs a bunch of duplication it seems....
lia41985
New member
I think I know something and then I realize I dipped out of class without even getting a hall pass.
Thank you, sir.
Here's to you:
<iframe width="420" height="315" src="http://www.youtube.com/embed/almbllyL7xk" frameborder="0" allowfullscreen=""></iframe>
That knowledge is nasty, son.
lia41985
New member
Why not consolidate these related subjects in one place? Is it really that messy? Seems like compelling thinking/discussion is occurring. At this point it only seems our understanding will be furthered.
Why focus on just a single dimensional aspect of the movement? Why the obsession when there's movement and forces in all three dimensions?
Also, because we are bilaterally symmetrical force producing beings a focus will be needed on each joint, in isolation.
As an example, let's start with the premise that the hips decelerate. In what plane of motion? How does the rate of acceleration/deceleration of the right hip compare to the left hip?
This is where simply referring to the motion through the prism of the "pelvis" narrows our frame of reference.
Another example: lust as the left and right wrists are both undergoing different ranges and rates of flexion and extension so are the left and right hips conceivably.
Kna mean?
<iframe width="420" height="315" src="http://www.youtube.com/embed/vW5K8E1Wkew" frameborder="0" allowfullscreen=""></iframe>
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lia41985
New member
If velocity is a vector with magnitude and direction...
And the "hips" are continually changing orientation through 3-D space throughout the sequence of the golf swing (i.e. time)...
And acceleration is change in velocity...
Are we talking about acceleration...?
Deceleration...?
Negative acceleration (not necessarily due to magnitude but change in "sign" due to change in direction within the field we've designated i.e. frame of reference)...?
...
Learning...
Is this the answer? (click this link): Positive Velocity and Negative Acceleration
And the "hips" are continually changing orientation through 3-D space throughout the sequence of the golf swing (i.e. time)...
And acceleration is change in velocity...
Are we talking about acceleration...?
Deceleration...?
Negative acceleration (not necessarily due to magnitude but change in "sign" due to change in direction within the field we've designated i.e. frame of reference)...?
...
Learning...
Is this the answer? (click this link): Positive Velocity and Negative Acceleration
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I can make the chair go both ways, without any perceivable effect on my thorax rotation.
Mike Richardson
New
Think you may have got this round the wrong way. Moving your thorax makes the chair go the opposite way. So the rotation of the thorax automatically puts the brakes on the pelvis.
By the way, after reading that stuff from madrin, I have to say that reading those graphs with no idea about
1. how they were measured
2. how the data was derived
3. who was measured
is a pretty pointless pursuit. Accepting this TPI stuff at face value is just silly.
A little knowledge is apparently dangerous.
1. how they were measured
2. how the data was derived
3. who was measured
is a pretty pointless pursuit. Accepting this TPI stuff at face value is just silly.
A little knowledge is apparently dangerous.
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