Question about Leadbetter Article

[natep]

The article is from Golf Digest, March 2007. It's titled "Find your Swing Chi"

Golfers were swinging on pressure plates so that their weight shift could be measured.
Pros and amateurs were compared. At the top of the backswing, the pros had 90% of their weight on the right foot, while the amateurs had 50%. At the start of the downswing, the pros had 110% of the weight on the left foot, while the amateurs had 65%. At impact, the pros had 25% of their weight on both feet, while the amateurs had 50%.

(Sorry, I scanned the image but I cant figure out how to attach it. I'm new here.)

Leadbetter says that the pros have 25% of their weight on their feet at impact "because they transferred 75% of their weight into the hit".

Is this really possible? My guess is that it happens because of a sort of jumping off the left foot at impact, but I'd like to know what you folks have to say about it. Thanks.

 

[greenfree]

The article is from Golf Digest, March 2007. It's titled "Find your Swing Chi"

Golfers were swinging on pressure plates so that their weight shift could be measured.
Pros and amateurs were compared. At the top of the backswing, the pros had 90% of their weight on the right foot, while the amateurs had 50%. At the start of the downswing, the pros had 110% of the weight on the left foot, while the amateurs had 65%. At impact, the pros had 25% of their weight on both feet, while the amateurs had 50%.

(Sorry, I scanned the image but I cant figure out how to attach it. I'm new here.)

Leadbetter says that the pros have 25% of their weight on their feet at impact "because they transferred 75% of their weight into the hit".

Is this really possible? My guess is that it happens because of a sort of jumping off the left foot at impact, but I'd like to know what you folks have to say about it. Thanks.

How can you have 110% of your weight on your left foot at the start of the d.s.? If i weigh 400lbs how do i get to 440 lbs in a micro second on my forward foot or anywhere for that matter , i know more donuts...lol Pressure might increase, different than weight , someone must have the answer?

 

[Bigwill]

How can you have more 110% of your weight on your left foot at the start of the d.s.? If i weigh 400lbs how do i get to 440 lbs in a micro second on my forward foot or anywhere for that matter , i know more donuts...lol

If you're using a scale, for instance, and you kind of jump up on the scale, when you land, the force you exert upon landing will read as more weight than than you weigh statically.

 

[kc8kir]

So non-scientific, it's scary...

Leadbetter must have been imagining a club where you could shoot mass down the shaft into the clubhead! I remember that article. I found it so non-sensical and non-scientific that as an engineer I had to stop reading it just so that I wouldn't suffer a mass brain hemorage.

The idea of transfering weight is ludricrous. It's a non-scientific expression of the human perception of balance and pressure. Actual pressure and its result on the dynamic motion is all that matters, and so far I have not seen a study done, with proper respect to physical laws, to correctly show pressure distributions throughout the swing and determine optimal patterns for execution of the golf swing (though.. what is optimum I ask... another line of questioning entirely).

 

[greenfree]

If you're using a scale, for instance, and you kind of jump up on the scale, when you land, the force you exert upon landing will effectively make you weigh more than your static weight.

Is that pressure or weight? or?

 

[Bigwill]

Is that pressure or weight? or?

Literally, you don't weigh more. So it's probably technically force or pressure that's being measured. But as far as the scale or your body are concerned, pounds are pounds

 

[greenfree]

Literally, you don't weigh more. So it's probably technically force or pressure that's being measured. But as far as the scale or your body are concerned, pounds are pounds

So i really weigh a lot more than i thought and don't laugh cus that means so does everyone else....

 

[kc8kir]

Is that pressure or weight? or?

It is a surface force... exerted by the deceleration of the falling body as it is impacted by the upward normal force of the ground (surface being impacted). Imbalance of forces = change in velocity = acceleration which by Newton's law (F=ma) equals a force. The pressure achieved is a force across an area (your foot, or part of your foot). Weight, is only your mass times the acceleration of gravity (approximately 9.82 meters / second / second). Your weight doesn't change (assuming constant gravity) and unless you are eating and swinging, your mass doesn't change either. Your exertion of force to the surface on which you are swinging, and the resulting measurements of force and pressure are what change.

Wheww... enough science talk.

If you want a really goofy problem, answer this. Is a golfer's dynamic pivot more effective at the equator or the poles? Lol...

 

[greenfree]

It is a surface force... exerted by the deceleration of the falling body as it is impacted by the upward normal force of the ground (surface being impacted). Imbalance of forces = change in velocity = acceleration which by Newton's law (F=ma) equals a force. The pressure achieved is a force across an area (your foot, or part of your foot). Weight, is only your mass times the acceleration of gravity (approximately 9.82 meters / second / second). Your weight doesn't change (assuming constant gravity) and unless you are eating and swinging, your mass doesn't change either. Your exertion of force to the surface on which you are swinging, and the resulting measurements of force and pressure are what change.

Wheww... enough science talk.

If you want a really goofy problem, answer this. Is a golfer's dynamic pivot more effective at the equator or the poles? Lol...

Doesn't that depend on how big the golfer's head and feet are in relation to his belly.? ...lol

 

[Bigwill]

So i really weigh a lot more than i thought and don't laugh cus that means so does everyone else....

Yeah, that's why stationary bikes and elipticals are so popular as cardio machines. If you are heavy, or have joint problems, there's no way you're gonna be able to run effectively enough to get a quality workout. You already have problems because you're heavy. So now, you "add weight" at every footstrike.

As far as the "unweighting" at impact, I'm sure that it has more to do with the golfer jumping up (think Laura Davies or most Long Drive pros at impact as extreme examples), and less to do with the golfer transmitting their weight into the ball...

 

[greenfree]

Yeah, that's why stationary bikes and elipticals are so popular as cardio machines. If you are heavy, or have joint problems, there's no way you're gonna be able to run effectively enough to get a quality workout. You already have problems because you're heavy. So now, you "add weight" at every footstrike.

As far as the "unweighting" at impact, I'm sure that it has more to do with the golfer jumping up (think Laura Davies or most Long Drive pros at impact as extreme examples), and less to do with the golfer transmitting their weight into the ball...

So that's why i feel lighter when i'm on the couch with my feet propped up and eating that extra cheeseburger.

 

[natep]

Yeah I would imagine that the pressure plates measure force, not just static weight. What I was unsure about was having only 25% of your total weight on both feet at impact. Does anyone know if it's optimal to sort of jump up through impact? It reminded me of a Tiger swing where I saw him slide his left foot backward away from the target line through impact as if he was jumping and turning simultaneously

[media]http://www.youtube.com/watch?v=W8N-N4FEoMY[/media]

 

[Dariusz J.]

Leadbetter says that the pros have 25% of their weight on their feet at impact "because they transferred 75% of their weight into the hit".
Is this really possible? My guess is that it happens because of a sort of jumping off the left foot at impact, but I'd like to know what you folks have to say about it. Thanks.

Yes. But he's obviously generalizing which is not good for readers. There are "jumpers" and "not-jumpers" - did you ever see Hogan or Moe jump at impact ? Nope. The trick is to know why some best ballstrikers never jumped off their shoes.

How can you have 110% of your weight on your left foot at the start of the d.s.? If i weigh 400lbs how do i get to 440 lbs in a micro second on my forward foot or anywhere for that matter , i know more donuts...lol Pressure might increase, different than weight , someone must have the answer?

The answer is in simple physics. The scale moved EXACTLY because your weight changed. The notion "weight" is always equal to a force:
- "statically" = your true mass x gravitational acceleration;
- "dynamically" = your true mass x gravitational acceleration +/- additional acceleration.
When you prepare to jump you create additional acceleration acting in the same direction as gravity, therefore, your weight changes which can be observed on the scales. What always remains unchanged is mass. Think astronauts on the Moon - their mass remains the same while their weight there decreased. Simple as that.

Cheers

 

[natep]

Is there any info anywhere on the merits of jumping vs. non-jumping, as it relates to efficiency or clubhead speed?

 

[greenfree]

Yes. But he's obviously generalizing which is not good for readers. There are "jumpers" and "not-jumpers" - did you ever see Hogan or Moe jump at impact ? Nope. The trick is to know why some best ballstrikers never jumped off their shoes.



The answer is in simple physics. The scale moved EXACTLY because your weight changed. The notion "weight" is always equal to a force:
- "statically" = your true mass x gravitational acceleration;
- "dynamically" = your true mass x gravitational acceleration +/- additional acceleration.
When you prepare to jump you create additional acceleration acting in the same direction as gravity, therefore, your weight changes which can be observed on the scales. What always remains unchanged is mass. Think astronauts on the Moon - their mass remains the same while their weight there decreased. Simple as that.

Cheers

I need a mass scale.

 

[natep]

The article doesnt state how many elite players were tested, but the results imply that the elite players were all "light non their feet" through impact. I would think that the average weight on the left foot would be higher if some of the players tested were non-jumpers.

 

[Bigwill]

Is there any info anywhere on the merits of jumping vs. non-jumping, as it relates to efficiency or clubhead speed?

I don't know about any info, per se, but I know that a lot of big hitters do it (jump).

 

[natep]

Yeah. My guess would be that it shortens the radius by lifting the left shoulder, but I'm not certain.

 

[spktho]

If you want a really goofy problem, answer this. Is a golfer's dynamic pivot more effective at the equator or the poles? Lol...

On Mount Everest or in Death Valley too?

Yeah. My guess would be that it shortens the radius by lifting the left shoulder, but I'm not certain.

Adds to yanking the "hoop" out of the ground.

 

[natep]

I'd be interested in seeing the results of a similar study. This Golf Digest article is not enough to convince me that impact weight/ground force is so low among good players.