Brian Manzella
Administrator
Seems to me, in a really good swing, you'd have decel shoulders and re-accel as the golfer pulls in at impact.
No?
No?
My feelings on Pivot Deceleration.
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You can't see that from those graphs, but I think they pull with left, or actually push up and back with left leg, so the shoulder moves and pulls the shaft to "normal" and on the same time they push with the right shoulder toward the target.
That last graph is right shoulder moves toward the target, and there is speed and orientation. The speed is only negative when the right shoulder moves away from the target at the first part of dsw (because of rotation it has to) and then it only accelerates.
So we can say that biggest part of deceleration shows only the change of direction in rotation. Not deceleration, even it seems like that.
They are synchronized at time. That's one problem when I can't include the video here, because now on graphs half way down it's not half way down at distance. That's why they are sometimes bit hard to read before get use to it.
Both lines are totally toward the target, speed and orientation. So only X is there, nothing from Y or Z
Michael Finney
New
I think we now understand that all the 3D measuring companies do their craft differently...... And as teeace has already said, the only way to compare and contrast swings is inside companies....not company to company.....end of discussion in this particular regard
Thats true and clear.
Now we only have this to be or not to be question left. What really happens with deceleration / acceleration and how player should threat that?
It goes really interesting when we start to look at the lateral hip speeds. Blue is back hip and red is front
Blue is back hip and red is front
Where exactly are the sensors placed to differentiate "back hip" and "front hip"?
There is no sensors, but the measurement points are about outer edge of the hip joints and at the middle if you look it from dtl view. Anyway it doesn't change much where they are, but definitely in hips, not lower back or near the spine.
So we are looking at about the femoral greater trochanter area of the "hips" turning, not pelvic turning?
This is where the more descriptive terms of anatomy comes in handy, so you can convey where exactly the measurements are taken on the body. In anatomy the "hip" joint is the femoral head and acetablum articulation which is pretty deep in the groin area. It is tough to get in there and measure movements invivo.
This is where the more descriptive terms of anatomy comes in handy, so you can convey where exactly the measurements are taken on the body. In anatomy the "hip" joint is the femoral head and acetablum articulation which is pretty deep in the groin area. It is tough to get in there and measure movements invivo.
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We can take any point from the body and go "inside" because it's video based system with model fitting. So we just decide the point how far from the center of pelvis, how deep and what height. Not that simple really, but don't want to say too much about that.
Anyway it doesn't change the case and it's relevant part.
I guess seeing some of the implied tone of some of the posts in this thread, I must go back and preface that I am not attacking you, your machine, or your teaching method(s).
That being said, that is pretty cool and would be very interesting to be able to measure the movements of many different points on the body. I was trying to see what relevance the comparison of "hips" graph was showing. If you take measurements comparing the motion of the two sides of the pelvis, does that show a "mirror" image of the movements for each side? Might be cool to see to test the measurements because we know the pelvis is pretty fixed and does not move much--it should show real close to equal movement on each side. I would think that would have been the first thing the manufacturers.
Oh, and that would be measuring more for the commonly thought rotational speed of the "hips".
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Any chance of getting the front hip and front shoulder up/down (y?) speed component graphs together with rotation speeds for a player that re-accelerates shoulder speed just before impact.
I think that for the hip/shoulder speeds, instead of what you call lateral speed (x = target line?) those should be rotational or absolute speeds in horizontal plane (x-z?), not pure x-component.
Or did you particular reason to use x component only?
They might be the same if the reference is rotation around the spine. However if you measure absolute speed, they can move at different speeds, even one could be stopped and one moving.
If that lateral speed in those Tees graphs is x-component only, then I would interpret it so that front hip is going away from target (below black line) just before impact when back hip keeps going toward target. That sounds logical anyway.
It's not so easy to understand 2d representation of 3d data unless projection & axes are clearly defined.
Ya, thanks, I'm just trying to figure out the 2d graph related to 3d movements.
Oh, no offense taken. I'm just quite busy sometimes and when answering, I might be too straight and sound impolite, but want to answer quickly.
In that graph is just both hips and that makes it interesting. You see just before impact the front hip (left) changes from positive lateral speed to negative, but at least it don't decelerate, just opposite. So IMO that's why he got his hip rotation speed peak at impact, because he kicks so hard back with his front leg just before impact.
Around the vertical axis, like they move.
But be careful when reading these. Last graphs has been about lateral speed, not rotation.
So lets go bit deeper here also. We found that right hip is decelerating before impact to that direction, but left hip is accelerating very strongly. Can we get some thoughts about rotation axle from that?
Tee: have I interpreted the graph correctly? It seems to me that the right shoulder is in continuous acceleration. What confuses me a bit is that the orientation and speed lines don't seem to tie in with each other ie the synchronisation seems "wrong".
You have to see the angle of the graph and that's even zoomed quite a lot and scaling can't be the same.
So when there is acceleration, the orientation line angle should change steeper, when it's moving stable speed, the orientation line should be level. Also notice, that the speed line is never zero after the impact, so orientation is still growing, but it's line is shallower than when there is acceleration.
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