anyone who is familiar with sonicgolf....

[Michael Finney]

if the accelerometor sensors are sitting in the handle of the club, are they measuring the speed of the hands or the club head - or some other section of the club?

the way the product is presented, i would understand it to be the club head speed....

 

[Kevin Shields]

Is that Grober's thing?

 

[niblick1]

Michael-

The sound that you hear in Sonic Golf is the data measuring "centripetal acceleration," which Grober says is a reasonable way of serving to measure the clubhead speed of the golfer.

There is a paper Grober just published that also looks at that clubhead speed data in relation to different data -- measuring hand acceleration -- to examine clubhead speed in relation to hand acceleration/deceleration in different levels of golfers.

Here's a link to that paper:

http://arxiv.org/ftp/arxiv/papers/1001/1001.1137.pdf

 

[Matt Bryda]

Yes, Dr. Grober's invention.
Does it measure what a bee bee would do if you had one inside the golf shaft?
and
Not the rotation of the left hand?

Matt

 

[niblick1]

Yes, Dr. Grober's invention.
Does it measure what a bee bee would do if you had one inside the golf shaft?
and
Not the rotation of the left hand?

Matt

There's a video on Grober's Sonic Golf website that explains how it works. The sound measures "rotation" and makes no sound if the club is just moving in a straight line back (eg, first few inches of takeaway if you use a lagging clubhead takeaway) or straight up and down. So in some sense it is measuring the "b-b in the shaft" in the backswing and downswing, but you can make the b-b move faster by also rotating the left hand, can't you? I'm not sure those are exclusive of each other.

 

[Matt Bryda]

but you can make the b-b move faster by also rotating the left hand, can't you?

Yes, for sure.
but not sure if they are mutually exclusive.

Matt

 

[Michael Finney]

finally got around to reading the linked article by grober....answered a lot of my questions....thanks

mandatory reading for those interested in the role of the hands in the downswing and the associated torques

 

[niblick1]

Michael, the Aspen lecture from Grober available on Google Video is well worth watching also. When you listen to his description of the "spring" of the golf swing, Brian's stressing of the snapping the kinetic chain and the "jump" in release, umm, "springs" to mind.

By the way, if i had to summarize as simply as possible what I think the sonicgolf system does is it uses two accelerometers in the shaft to measure acceleration in the handle vs. a spot further along the shaft to provide a sound output that tells you how fast the clubshaft is moving versus the handle in a circle around a hub. The speed of movement in a circle is converted into sound. If the handle and clubhead are moving at the same speed (eg, dropped off a building and falls straight down) there is no sound. The sound would be louder the faster it swings in a circle, think a tiny very fast merry-go-round.

 

[Michael Finney]

please see my above edited post......a great paper by grober and very understandable...thanks also for your explanations, niblick - they are very helpful also...

 

[EdStraker]

Here is a link to the Grober video:

[media]http://video.google.com/videoplay?docid=4219126936537965659&ei=7eB2S4OuCqXKqwLi0fTYBw&q=grober+&hl=en#[/media]