bio feedback

[mandrin]

Feedback on bio feedback ??

This thread is being high jacked by someone having a narcissistic personality disorder. Anything will do to attract the attention. Strange formatting, aggressive colors, extravagant claims, it is all part of a continuous scheme to keep attracting the attention.

The last posts are indeed rather hilarious. It is claimed to know the final truth about golf but for some reasons can’t discuss them. Why not a have a section set aside, “Alice in Golf Wonderland”, so that Bronco Billy can have a nice place for him to indulge in his ‘mirror‘ activities.

What about coming back to business and having some posts about biofeedback for a change. I find it hard to accept that there isn’t someone who has some sensible comments on the subject. Don’t make me feel being stuck with Bronco Billy in this thread. I am getting dazzled by all the emphasis and aggressive colors being used continuously.

 

[Damon Lucas]

My thoughts, Mandrin...

Biofeedback is a good way to fine tune whatever it is the teacher is trying to get you to do, but must be used with a more conscious and thoughtful attempt to produce the desired move with zero feedback, for long term improvement.

That is, do a biofeedback session, then, do 5 or 10 measured swings without feedback, and correlate the results.

 

[GaryC_47]

What about coming back to business and having some posts about biofeedback for a change.

Mandrin,

Do you think the location of the 2nd sensor would have a major impact on the output?

The prototype system had the 2nd sensor located down the shaft close to the club head. The 2nd sensor in the production system is located much closer to the butt end sensor - looks like about the length of a grip apart.

It seems to me that the production version would be measuring only the speed of the hands while the prototype was measuring the hands and the club head. So shaft flex would not be as much a factor in the output of the production version?

 

[mandrin]

Dr Robert Neal / ''Golf Biodynamics / biofeedback

My thoughts, Mandrin...

Biofeedback is a good way to fine tune whatever it is the teacher is trying to get you to do, but must be used with a more conscious and thoughtful attempt to produce the desired move with zero feedback, for long term improvement.

That is, do a biofeedback session, then, do 5 or 10 measured swings without feedback, and correlate the results.

Kevin,

To furnish some further food for thought I have reproduced some text from an article in the may 2007 issue of www.golfinternationalmag.com about Dr Robert’s Golf Biodynamics system


Biomechanics and biofeedback are transforming our understanding of the golf swing as well as our approach to
instruction, practice and physiotherapy.

It’s ironic that for all the frantic emphasis on science and technology in so many areas of the golf industry, golf instruction remains widely perceived as an art.
Equipment companies blind us with science, while elaborate launch monitors measure our ball speed down to the last m.p.h. as well as every last RPM of spin and degree of launch angle as the ball leaves the clubface.
Yet few of us ever think of measuring the various components of our actual golf swing, the biomechanical movements of the body that, rather fundamentally, deliver the blow in the first place.
OK, so much of today’s golf instruction may look high-tech – and video analysis is obviously a start with slow motion replays, coloured lines and overlays certainly helping the learning process.
But in terms of the true science of what is really going on in our swing – and especially the vital elements that generate power and consistency – most traditional instruction methods do not give us the true picture.
For as many experts acknowledge, the dynamics of the golf swing are such that many of the most important positions, sequences, speeds and timing nuances cannot be appreciated with the naked eye and, in some cases, even slow-motion video.
Hence the rise of cutting-edge, three-dimensional swing analysis technology that uses the principles of biomechanics to address these issues.
“Even the very best teachers cannot accurately assess, using their eyes alone, subtle movements and body orientations during the golf swing,” says Rob Neal, whose Golf Biodynamics system is the subject of this feature.
“As well as speeds and timing, the bending, tilting and rotation of the pelvis and shoulders, along with head thrusting and hip turn, are just some of the crucial elements that are hard to spot.”
Having intrigued a range of top tour stars, including Nick Faldo, Angel Cabrerra and Camillio Villegas, Neal’s fascinating system is steadily revolutionizing golf instruction.
As far back as 1985, Neal was among the first golf ‘scientists’ to recognize that 3-D was the key – not merely viewing the swing in three dimensions but measuring, numerically, the relevant angles, distances and speeds involved for all the relevant positions and movements.

Above constitutes a rather interesting view on the present state of affairs.

Kevin what do particularly think about the remarks below more specifically related to the biofeedback aspect of learning ?

BIOFEEDBACK THE ULTIMATE TRAINING AID ?

As well as analyzing your swing and instantly identifying the areas to work on, the Golf Biodynamics system also includes a novel audio feedback feature that greatly speeds up the learning process by ingeniously helping you to ‘feel’ the correct positions and movements.
The coach first chooses a particular swing parameter and assigns a range of values that represents an appropriate margin of error within which to work.
The golfer uses this to move himself into the correct positions as confirmed by a constant audible ’beep’ tone from the computer.
Moving outside this ‘corridor’ will interrupt the signal, with the silence immediately the golfer that has deviated from the desired position or movement.
Sure, there are a proliferation of ‘feel-related’ training aids on the market these days, ranging from huge circular swing-planes, to mirrored floors and laser-equipped visors.
But the beauty of this type of biofeedback is that you can assign it to any part of the swing at the touch of a button.

 

[mandrin]

Mandrin,

Do you think the location of the 2nd sensor would have a major impact on the output?

So shaft flex would not be as much a factor in the output of the production version?

Gary,

Only somewhat less signal strength but no problem as optimum accuracy of measurement is not an issue.

The shaft flex does not really come into the picture, one way or another.

The location of the sensor is likely dictated by very mundane practical reasons.

 

[mandrin]

Totally agree in the case of perfect ball-club contact. What I wanted the good people of this forum to think about is when some outside agent, grass/turf/mud on ball interferes with the club before impact.

Would acceleration/deceleration matter if you consider interference of grass/mud/turf between ball and clubhead?

I mentioned my intuition here because I was thinking about the difference in time to slow down a car when your foot is to the floor (accelerating), compared to when you are cruising (no acceleration).

Isn't this analogous to what happens in the rough? (the break/friction is the grass/turf). What will happen to the coefficient of restitution in this case?

My understanding of classical physics says acceleration doesn't effect an objects momentum (mv). But an accelerating mass has a force associated with it. Would this force help in overcoming any resistance of turf/grass on the way to the ball?

I think of this slight acceleration of clubhead at impact to a 'buffer' amount of energy stored in the swing which helps overcome any extra resistance from grass, a none-accelerating clubhead would not have this force, albeit having more kinetic energy. The end-result being that the none-accelerating swing has a much larger variance of distance in shots from rough compared to the accelerating swing.

I apologize if my science is terrible, it's been a while since Physics A-Level and would appreciate corrections from those who know better and can help me sleep peacefully at night once more about this worrisome topic!

Strange isn't it? My whole thinking on this is basically due to changing my swing to increase my lag. I've noticed that after these changes; occasionally I hit a shot that 'feels' fat but the actual distance is same as expected.
(I check all my yardages with a laser rangefinder.

Cheers,
Dominic

Dominic,

Your thinking is based on the premise that we can somehow influence the club head’s acceleration/deceleration during impact. However, whatever happens during impact is not under control of the golfer. He might be for almost all of the of the down swing but not for that tiny 0.0004 sec of impact duration. Any substance such as grass between ball and clubface, during impact, again is totally a matter of impact physics, primarily the friction coefficient.

 

[dominicscaife]

Confused still.

Dominic,

Your thinking is based on the premise that we can somehow influence the club head’s acceleration/deceleration during impact. However, whatever happens during impact is not under control of the golfer. He might be for almost all of the of the down swing but not for that tiny 0.0004 sec of impact duration. Any substance such as grass between ball and clubface, during impact, again is totally a matter of impact physics, primarily the friction coefficient.

Thanks for the response Mandrin. I do acknowledge we cannot influence club head acceleration after impact.

I was actually thinking more about initial conditions the instant before impact. (In a similiar way to chaos theory where very small differences in initial conditions lead to big changes in output e.g. Hadamard's billiards)

Is the clubhead accelerating or at max velocity already?

Would you rather be hit by a car travelling at 30mph accelerating or decelerating? Would it indeed make a difference?

I acknowledge that momentum is the same. But where does that accelerating force (mass x acceleration) go?

 

[mandrin]

Thanks for the response Mandrin. I do acknowledge we cannot influence club head acceleration after impact.

I was actually thinking more about initial conditions the instant before impact. (In a similiar way to chaos theory where very small differences in initial conditions lead to big changes in output e.g. Hadamard's billiards)

Is the clubhead accelerating or at max velocity already?

Would you rather be hit by a car travelling at 30mph accelerating or decelerating? Would it indeed make a difference?

I acknowledge that momentum is the same. But where does that accelerating force (mass x acceleration) go?

Thanks for the response Mandrin. I do acknowledge we cannot influence club head acceleration after impact.

dominicscaife, I am not referring to after impact but to the time interval during impact.

I was actually thinking more about initial conditions the instant before impact. (In a similiar way to chaos theory where very small differences in initial conditions lead to big changes in output e.g. Hadamard's billiards)

I am sure that you many love to see chaos theory introduced into the golf swing. It gives them a ready excuse when things go wrong.

Is the clubhead accelerating or at max velocity already?

You really have to consider something very simple and basic. Maximum velocity by definition invokes zero acceleration.

Would you rather be hit by a car travelling at 30mph accelerating or decelerating? Would it indeed make a difference?

Again consider something very basic – In general impacts are so short in duration that any possible acting external forces can be ignored. Hence just velocity, nothing else matters.

I acknowledge that momentum is the same. But where does that accelerating force (mass x acceleration) go?

Again your premise is wrong. External forces, accelerations, forget them. Just focus on velocity.

 

[GaryC_47]

Gary,

Only somewhat less signal strength but no problem as optimum accuracy of measurement is not an issue.

The shaft flex does not really come into the picture, one way or another.

The location of the sensor is likely dictated by very mundane practical reasons.

Mandrin,

Thanks. I'm not sure I understand why the shaft flex is is of no consequence here. Perhaps you can make this more clear for me. I'll try to give an example.

Let's say I had two shafts, A & B, with screw-on connectors to allow me to use the same club head, a robot swinging at the same speed, and Trackman measured the club head speed with shaft A as 100 mph and shaft B as 95 mph.

Two swings with each shaft. Swing (1) with sensors at the butt and about 10" down the shaft; swing (2) with sensors at the butt and 25" down the shaft.

Would the sounds be approximately the same for all four swings? i.e. A(1) = A(2) = B(1) = B(2) or would A(1) = A(2) and B(1) = B(2)?

I would think that A(1) = B(1) only.

I just ordered a system and I'm wondering if it would be useful in club fitting as well as teaching.

thanks,
Gary

 

[mandrin]

Mandrin,

Thanks. I'm not sure I understand why the shaft flex is is of no consequence here. Perhaps you can make this more clear for me. I'll try to give an example.

Let's say I had two shafts, A & B, with screw-on connectors to allow me to use the same club head, a robot swinging at the same speed, and Trackman measured the club head speed with shaft A as 100 mph and shaft B as 95 mph.

Two swings with each shaft. Swing (1) with sensors at the butt and about 10" down the shaft; swing (2) with sensors at the butt and 25" down the shaft.

Would the sounds be approximately the same for all four swings? i.e. A(1) = A(2) = B(1) = B(2) or would A(1) = A(2) and B(1) = B(2)?

I would think that A(1) = B(1) only.

I just ordered a system and I'm wondering if it would be useful in club fitting as well as teaching.

thanks,
Gary

Gary,

The instrument converts the measured radial acceleration along the shaft into angular velocity of the shaft at the point where the accelerometers are inserted. This velocity signal is converted into sound of varying pitch and amplitude. The system does measure angular velocity, not linear velocity; hence any linear motion of the shaft doesn’t produce any signal. Also the flexing of the shaft really should not give any noticeable difference in the audio output signal since it really does not influence the radial acceleration.

If you take an identical accelerometer and put it in different locations surely will produce different output magnitudes signal. Probably in later version for practical reasons perhaps put closer to the hands, maybe for greater reliability, less impact shock,. Your thought experiment uses them in a way for which they are not meant. You buy them with the accelerometers at one fixed location. But even so, assuming that one does your experiment, quite likely adjusting the volume on either one system should make A equal to B and the two systems are not distinguishable.

To develop some form of sonic biofeedback system which would indicate reliably the amount of flexing of the shaft to be used for some form of dynamic shaft fitting would be a rather interesting technical challenge. Much more so than the design of Dr Robert’s sonic system which is very sound, robust and elegant in its design.

However if you are truly interested I would go directly to the source for information and not rely on my ideas on the subject. I can only make some educated guesses.

 

[dominicscaife]

Not convinced.

Is the clubhead accelerating or at max velocity already?

You really have to consider something very simple and basic. Maximum velocity by definition invokes zero acceleration.

Of course, that's why I said 'or'. Perhaps my wording was weak, sorry for that.

I should have phrased it like this: 'Is the clubhead accelerating or does it have constant velocity or is it decelerating?

My original hypothesis was which of these possibilities is optimal for obtaining consistency.

I acknowledge that momentum is the same. But where does that accelerating force (mass x acceleration) go?

Again your premise is wrong. External forces, accelerations, forget them. Just focus on velocity.

I'm not convinced. Can you explain why we can discount this?

I suspect slight acceleration at impact leads to more consistency because that's what good players in general do.

Evidence to support this:
1.
The graph you posted to begin this thread shows a tour pro's trace with acceleration still increasing at impact.

2.
The 'low handicap players' who tried Dr Grober's club after his talk all had max velocity after ball.

Evidence to discount this:
1. Nesbit: Noticed in Nesbit's study the scratch player has max velocity right before impact (no acceleration)

Would like to see more data!

 

[mandrin]

Of course, that's why I said 'or'. Perhaps my wording was weak, sorry for that.

I should have phrased it like this: 'Is the clubhead accelerating or does it have constant velocity or is it decelerating?

My original hypothesis was which of these possibilities is optimal for obtaining consistency.



I'm not convinced. Can you explain why we can discount this?

I suspect slight acceleration at impact leads to more consistency because that's what good players in general do.

Evidence to support this:
1.
The graph you posted to begin this thread shows a tour pro's trace with acceleration still increasing at impact.

2.
The 'low handicap players' who tried Dr Grober's club after his talk all had max velocity after ball.

Evidence to discount this:
1. Nesbit: Noticed in Nesbit's study the scratch player has max velocity right before impact (no acceleration)

Would like to see more data!

dominicscaife,

I suggest searching a bit in the archives and perhaps taking 'golf-impact-physics ' for reading as a starting point. It makes discussion a bit easier when having some common ground.

I think it is ancient history the knowledge that high handicappers typically have their peak velocity before impact. Instructors might instructs their pupils to feel like as if they produce maximum velocity beyond impact. This might appears as accelerating through impact.

Dr Grober's experimental research with amateurs, pros and long distance pros alike shows up very clearly there to be no late hit. Maximum torque and acceleration occur before impact. Rather more like the old concept of 'free wheeling' the club through impact. Brian with his own research efforts has come to similar conclusions.

Please look again carefully, the lower trace in the graph shown in the opening post shows substantial deceleration of the hands before impact.

 

[GaryC_47]

Gary,

Your thought experiment uses them in a way for which they are not meant.

OK. Thanks Mandrin. My misconception of how the sensors worked...

I will still experiment with different shafts. Perhaps it will be possible to determine audibly if a particular shaft makes it easier for the golfer to release at the optimum point in the downswing.

Gary

 

[dominicscaife]

dominicscaife,

I suggest searching a bit in the archives and perhaps taking 'golf-impact-physics ' for reading as a starting point. It makes discussion a bit easier when having some common ground.

I think it is ancient history the knowledge that high handicappers typically have their peak velocity before impact. Instructors might instructs their pupils to feel like as if they produce maximum velocity beyond impact. This might appears as accelerating through impact.

Dr Grober's experimental research with amateurs, pros and long distance pros alike shows up very clearly there to be no late hit. Maximum torque and acceleration occur before impact. Rather more like the old concept of 'free wheeling' the club through impact. Brian with his own research efforts has come to similar conclusions.

Thanks for the links, Mandarin. I don't follow the logic in your impact paper.
Why do large forces at impact mean that one can ignore whether the clubhead is accelerating or decelerating at impact? I don't understand the rationale for this assumption saying that other forces in the system are negligible in comparison. Would you mind spelling it out?

Please look again carefully, the lower trace in the graph shown in the opening post shows substantial deceleration of the hands before impact.

I'm looking at the upper trace, which I thought (could be wrong it's a bit blurry) was clubhead acceleration. It's definately increasing before impact, albeit not max acceleration by any means.

Cheers!
Dominic

 

[mandrin]

Thanks for the links, Mandarin. I don't follow the logic in your impact paper.

Why do large forces at impact mean that one can ignore whether the clubhead is accelerating or decelerating at impact? I don't understand the rationale for this assumption saying that other forces in the system are negligible in comparison. Would you mind spelling it out?

I'm looking at the upper trace, which I thought (could be wrong it's a bit blurry) was clubhead acceleration. It's definately increasing before impact, albeit not max acceleration by any means.

Cheers!
Dominic

dominicscaife,

Forget science and just use common sense. If during impact, the forces, exerted by ball on clubhead and vice versa, can readily exceed 3000 lbs, how do you think a golfer can do anything to compete with such a large force using a flexible shaft, sideways, acting on the ball for only 0.0004 sec, whilst he is trying to keep up with a fast releasing club. Why do you think it makes a difference if the club is accelerating or decelerating just prior to and at impact? I am very interested to hear your arguments.

There is acceleration and there is acceleration, don't put them all in the same basket. A mass whirling rapidly around a steady center will indicate to have, when measured along the string, a very large acceleration. Yet the speed with which the mass circulates around the center is constant. The upper trace shows the centripetal acceleration which is proportional to the tangential velocity squared. Hence just think of the upper trace as an indicator for the clubhead speed.

 

[vjsinger]

How many instructors on this site use this technology?

Kevin,

To furnish some further food for thought I have reproduced some text from an article in the may 2007 issue of www.golfinternationalmag.com about Dr Robert’s Golf Biodynamics system


Biomechanics and biofeedback are transforming our understanding of the golf swing as well as our approach to
instruction, practice and physiotherapy.

It’s ironic that for all the frantic emphasis on science and technology in so many areas of the golf industry, golf instruction remains widely perceived as an art.
Equipment companies blind us with science, while elaborate launch monitors measure our ball speed down to the last m.p.h. as well as every last RPM of spin and degree of launch angle as the ball leaves the clubface.
Yet few of us ever think of measuring the various components of our actual golf swing, the biomechanical movements of the body that, rather fundamentally, deliver the blow in the first place.
OK, so much of today’s golf instruction may look high-tech – and video analysis is obviously a start with slow motion replays, coloured lines and overlays certainly helping the learning process.
But in terms of the true science of what is really going on in our swing – and especially the vital elements that generate power and consistency – most traditional instruction methods do not give us the true picture.
For as many experts acknowledge, the dynamics of the golf swing are such that many of the most important positions, sequences, speeds and timing nuances cannot be appreciated with the naked eye and, in some cases, even slow-motion video.
Hence the rise of cutting-edge, three-dimensional swing analysis technology that uses the principles of biomechanics to address these issues.
“Even the very best teachers cannot accurately assess, using their eyes alone, subtle movements and body orientations during the golf swing,” says Rob Neal, whose Golf Biodynamics system is the subject of this feature.
“As well as speeds and timing, the bending, tilting and rotation of the pelvis and shoulders, along with head thrusting and hip turn, are just some of the crucial elements that are hard to spot.”
Having intrigued a range of top tour stars, including Nick Faldo, Angel Cabrerra and Camillio Villegas, Neal’s fascinating system is steadily revolutionizing golf instruction.
As far back as 1985, Neal was among the first golf ‘scientists’ to recognize that 3-D was the key – not merely viewing the swing in three dimensions but measuring, numerically, the relevant angles, distances and speeds involved for all the relevant positions and movements.

Above constitutes a rather interesting view on the present state of affairs.

Kevin what do particularly think about the remarks below more specifically related to the biofeedback aspect of learning ?

BIOFEEDBACK THE ULTIMATE TRAINING AID ?

As well as analyzing your swing and instantly identifying the areas to work on, the Golf Biodynamics system also includes a novel audio feedback feature that greatly speeds up the learning process by ingeniously helping you to ‘feel’ the correct positions and movements.
The coach first chooses a particular swing parameter and assigns a range of values that represents an appropriate margin of error within which to work.
The golfer uses this to move himself into the correct positions as confirmed by a constant audible ’beep’ tone from the computer.
Moving outside this ‘corridor’ will interrupt the signal, with the silence immediately the golfer that has deviated from the desired position or movement.
Sure, there are a proliferation of ‘feel-related’ training aids on the market these days, ranging from huge circular swing-planes, to mirrored floors and laser-equipped visors.
But the beauty of this type of biofeedback is that you can assign it to any part of the swing at the touch of a button.

Just wondering how many of the Instructors here use this type of technology(k-vest,I-club) on a day to day basis. Furthermore, can you discuss results with students if possible. If this has been discussed at length before I apologize, and request direction to information.

 

[Brian Manzella]

Just wondering how many of the Instructors here use this type of technology(k-vest,I-club) on a day to day basis. Furthermore, can you discuss results with students if possible. If this has been discussed at length before I apologize, and request direction to information.

I have access through a good friend, of TrackMan, and 6° 3D. I have learned TON and I am sure that you folks on the forum have as well through my writings on these newfound facts.

It is AMAZING that folks STILL argue with the idea that impact can be changed somehow with any kind extra force or what happens before impact, or what would happen AFTER if there was no ball.

And still think that the HANDS NEED TO BE SPEEDING UP.

GEEZ....

 

[vjsinger]

What would be more important to an instructor??

I have access through a good friend, of TrackMan, and 6° 3D. I have learned TON and I am sure that you folks on the forum have as well through my writings on these newfound facts.

It is AMAZING that folks STILL argue with the idea that impact can be changed somehow with any kind extra force or what happens before impact, or what would happen AFTER if there was no ball.

And still think that the HANDS NEED TO BE SPEEDING UP.

GEEZ....

Brian,

I your opinion, what would be more valuable to the instructor in correctly identifying a students weaknesses. If you had the choice to only purchase one of these instruments for your use on a DAILY basis...Trackman,or the device Dr. Robert Neal has developed...Which would you choose and WHY?

Thanks.VJ

 

[Guitar Hero]

Brian,

I your opinion, what would be more valuable to the instructor in correctly identifying a students weaknesses. If you had the choice to only purchase one of these instruments for your use on a DAILY basis...Trackman,or the device Dr. Robert Neal has developed...Which would you choose and WHY?

Thanks.VJ

TrackMan or Flight Scope should be #1 on the list for serious golfers and instructors.