Power Sources in Golf

[AbsoluteTruths]

Chuck Evans just put out a new video about power sources in golf. The research surprised me. Over 50% of the power is in the forwarms and wrist action.
I went out back and tried focusing on that action with some slow swings and the swoosh through impact was surprising.

Chuck Evans Power Sources in Golf

[dennyjones]

thanks for the share.

[vangator]

It would be interesting to see exactly how he came up with 50%.  I could see setting up an Iron Byron to hit with wrist action and no wrist action.  I would think it would be hard to do with a real golfer and get reliable data.  Have you ever tried swinging with no wrist action?  That would be awkward if not impossible.

Plus, I don't know if I'd call it "power" as much as I'd call it "club head" speed.  May be just semantics.

[SavvySwede]

Quote from Erik

Quote

Most people talk only about the vertical GRF. But those are a small portion of the GRF, and within the swing itself, an even smaller portion of the contribution to swing speed.

Just swinging your arms is about 75% of your swing speed.

The horizontal ("rotational") speed (seen in shear GRF forces) are about 20%.

The vertical GRF stuff is about 5%. And most people already use a bit of that - almost nobody uses 0% of that 5%.

 

[iacas]

32 minutes ago, vangator said:

Plus, I don't know if I'd call it "power" as much as I'd call it "club head" speed.  May be just semantics.

Same thing. What else could "power" be? It's clubhead speed.

And, yeah, @SavvySwede, I stand by those numbers based on our research, but this is presented as the contribution from the legs, core, shoulders, etc. So, it's thought of a bit differently.

[AbsoluteTruths]

35 minutes ago, vangator said:

It would be interesting to see exactly how he came up with 50%.

This is the source: "Source of percentages I talked about, Phil Cheetham, PhD biomechanics" it is right under the video on the linked site.

[Marty2019]

1 hour ago, AbsoluteTruths said:

Chuck Evans just put out a new video about power sources in golf. The research surprised me. Over 50% of the power is in the forwarms and wrist action.
I went out back and tried focusing on that action with some slow swings and the swoosh through impact was surprising.

Chuck Evans Power Sources in Golf

I disagree with this video.   I have a very different theory about the golf swing.  

I understand that you can stand there and hit a ball with your wrists only like he did.    Where I disagree is the idea that your wrist and forearm muscles can contribute any power to a full swing.   In a full swing, the clubhead releases at such a high speed that if you try to "help" it forward with wrist and forearm muscles, you will only wind up holding it back.   The way clubhead speed is generated is from the rotation of your body, from the legs up through the torso and shoulders.    The clubhead release comes from a sudden deceleration of body rotation.  It's a whip-like action.  Take a look at a pro golfer's swing and you will see them slam on the brakes when they release the club.  Just like cracking a whip. Their hips stop for a split second as the clubhead releases.   That's why Rory McIlroy was doing squats in his tweet the other day.   He uses his thighs to slam on the brakes and stop his hip rotation when he releases the club. 

The golf swing is a double-pendulum.   When the top of the pendulum stops, the bottom of the pendulum picks up all that energy and the clubhead swings at a very high rate of speed.   But the only way to do this effectively is to take your hands and arms out of the equation.   Do not use your hands and forearms to try to propel the clubhead forward, because they cannot possibly keep up.   They will only hold the swing back.  

It takes a very strong, very well-coordinated person with quick-twitch muscles in his arms to use his hands and forearms to actually propel the club forward.  That person is very rare. 

"...to me, the legs and body are the engine of the golf swing; they fuel and drive it.  The arms are simply connecting rods to the club.  I regard the hands as linkage; hinges through which power, first as leverage and then as centrifugal force, is transmitted to the clubhead."   Jack Nicklaus, Golf My Way

So, hands and arms contributing to power in the golf swing?   I call bullshit on that. 

Feel free to demolish my argument.   I won't be offended if you do. 

 

 

[iacas]

32 minutes ago, Marty2019 said:

I disagree with this video.   I have a very different theory about the golf swing.

That's fine, but at the same time… you do realize who Phil Cheetham is, yes?

I'm all for questioning "experts" but I'm pretty cautious with some. Especially if I don't have much to go on.

32 minutes ago, Marty2019 said:

I understand that you can stand there and hit a ball with your wrists only like he did.    Where I disagree is the idea that your wrist and forearm muscles can contribute any power to a full swing.   In a full swing, the clubhead releases at such a high speed that if you try to "help" it forward with wrist and forearm muscles, you will only wind up holding it back.

I think your disagreement is simply a matter of definitions or context.

Very little power comes from the active use of your wrist muscles to snap the clubhead into the ball.

A substantial amount of speed comes from the angles of the wrist doing what they do, somewhat passively, to hit the ball.

Obviously that amount varies by the type of shot (a driver was used in these tests to get these percentages). For example, in a chip shot you could actively use the wrists to generate speed. And with a driver, I have little doubt that some long drive guys use their wrists a little bit. You and I? Probably less. But the angle still comes out, and it still directly contributes to clubhead speed.

So I think you're just off in how they're saying the "wrists" contribute. They aren't saying you actively fire the wrist muscles. I think they're just talking about the angle coming out - for example, if you made a swing where you actively tried to keep the wrist straight (no hinging, cocking, rolling, etc.).

32 minutes ago, Marty2019 said:

The way clubhead speed is generated is from the rotation of your body, from the legs up through the torso and shoulders.   

Your arms moving across your body generate most of the clubhead speed (this includes the wrists doing what they do, too, and the forearms). Most of the power in the golf swing comes from your arms. See the post above @SavvySwede quoted.

I fairly firmly believe this to be accurate, as we've worked with Ph.D.s to arrive at that conclusion.

32 minutes ago, Marty2019 said:

The clubhead release comes from a sudden deceleration of body rotation.  It's a whip-like action.

That doesn't really happen. You're seeing a result, not a cause. Just like my "coil" post in Swing Thoughts, if you suddenly stopped all motion of your torso in the downswing, you'd lose clubhead speed, not increase it. There's little conservation of angular momentum in the golf swing.

Here's a fairly good kinematic sequence.

It shows the pelvis (red), upper body (green), and the hands (blue) accelerating on the downswing in sequence. This has more to do with simply firing the right muscles at the right times, and with ranges of motion - many players can't really keep opening their hips at that rate where it peaks because they've reached the end of their range of motion (but that range then keeps getting extended because the torso keeps catching up).

It's possible to have a graph that doesn't look like this, too - it's possible to have hand speed peak at the wrong time, BEFORE the hips slow down, or the torso. They don't contribute much to the distal segment. Them slowing down also, really, slows down the segment they're attached to.

Your muscles are firing to do all of these things, particularly your arms and chest to move the arms across your body and into the ball.

The rotational aspect of the golf swing adds less than half of the speed in the golf swing. 20-25% or so. Try it - make a swing where you just rotate (don't use any vertical GRF either). Hold both of your arms really straight so you can't use them at all. Ball's not going very far.

Now, what it feels like to someone, well, that may be totally different. They may feel a "whip like" action though there isn't really one.

32 minutes ago, Marty2019 said:

Take a look at a pro golfer's swing and you will see them slam on the brakes when they release the club.

Not really what's happening. Many of them are at the edge of their range of motion at that moment in time. They're also doing some other things - the vertical GRF spikes from A6 to A7, for example, and that puts different forces and stresses and motions into play.

32 minutes ago, Marty2019 said:

He uses his thighs to slam on the brakes and stop his hip rotation when he releases the club.

Rory has always been long, even when he was a bit doughy. He's said he's building up his muscles as injury prevention, because he's had degenerative disc stuff already, not so much to gain speed. He's always hit the ball far, even before he was working out like he is now.

32 minutes ago, Marty2019 said:

The golf swing is a double-pendulum. When the top of the pendulum stops, the bottom of the pendulum picks up all that energy and the clubhead swings at a very high rate of speed. But the only way to do this effectively is to take your hands and arms out of the equation.   Do not use your hands and forearms to try to propel the clubhead forward, because they cannot possibly keep up.   They will only hold the swing back.

Again, yeah, I don't think that's what Phil Cheetham is saying.

Plus, the players DO actively move their arms across their chests. Absolutely they do.

32 minutes ago, Marty2019 said:

"...to me, the legs and body are the engine of the golf swing; they fuel and drive it.  The arms are simply connecting rods to the club.  I regard the hands as linkage; hinges through which power, first as leverage and then as centrifugal force, is transmitted to the clubhead."   Jack Nicklaus, Golf My Way

Let's get past quoting good golfers and look at the actual science, eh? We can do that these days.

32 minutes ago, Marty2019 said:

So, hands and arms contributing to power in the golf swing?   I call bullshit on that. 

Feel free to demolish my argument.   I won't be offended if you do. 

Of course they generate quite a bit of speed. This video shows the legs being taken out of it, and almost all rotation being taken out of the golf swing. Dave is able to generate 70% or so of his normal clubhead speed… just by swinging his arms.

[saevel25]

 

15 minutes ago, iacas said:

 

Of course they generate quite a bit of speed. This video shows the legs being taken out of it, and almost all rotation being taken out of the golf swing. Dave is able to generate 70% or so of his normal clubhead speed… just by swinging his arms.

To quote the term "seeing is believing." This is a great video showing just how influential the arms are in the golf swing. 

Look how far you can hit a punch shot when you have a restricted backswing. You can hinge the golf club to A2-A3 and really hit the ball a good distance. 

[Lihu]

I think telling people half the power in a swing is in the wrist action without explicitly detailing everything else in the kinematic sequence is going to cause some confusion.

[vangator]

8 hours ago, iacas said:

Same thing. What else could "power" be? It's clubhead speed.

And, yeah, @SavvySwede, I stand by those numbers based on our research, but this is presented as the contribution from the legs, core, shoulders, etc. So, it's thought of a bit differently.

I think there is a difference.  I believe a golfer with a powerful swing will have less rebound of the club head at impact than a person with a weak swing when both have the same club head speed.  The ball greatly deforms when it hits the club face and someone that can "force" the club head through will create more force than a swing that causes the club head to "bounce back".  No empirical data, just  what I believe.

[iacas]

10 minutes ago, vangator said:

I think there is a difference.  I believe a golfer with a powerful swing will have less rebound of the club head at impact than a person with a weak swing when both have the same club head speed.  The ball greatly deforms when it hits the club face and someone that can "force" the club head through will create more force than a swing that causes the club head to "bounce back".  No empirical data, just  what I believe.

Thanks for clarifying.

There is no such thing as force in the way you said. The only part of the club that plays a role during impact is the head and bottom few inches of the shaft.

[vangator]

8 hours ago, iacas said:

Thanks for clarifying.

There is no such thing as force in the way you said. The only part of the club that plays a role during impact is the head and bottom few inches of the shaft.

I believe Newton's Third Law of Motion (For every action there is an equal and opposite reaction) would apply here.  Since the ball stays in contact with the clubface as it deforms, a clubface that doesn't rebound as much should apply more force.  If I were to create an experiment, I would go in with that hypothesis.  Could be wrong.

Edited February 23, 2016 by vangator

[Ernest Jones]

8 hours ago, vangator said:

I think there is a difference.  I believe a golfer with a powerful swing will have less rebound of the club head at impact than a person with a weak swing when both have the same club head speed.  The ball greatly deforms when it hits the club face and someone that can "force" the club head through will create more force than a swing that causes the club head to "bounce back".  No empirical data, just  what I believe.

If they both have the same clubhead speed, how can one be weak and one be powerful?

[Lihu]

6 hours ago, vangator said:

I believe Newton's Third Law of Motion (For every action there is an equal and opposite reaction) would apply here.  Since the ball stays in contact with the clubface as it deforms, a clubface that doesn't rebound as much should apply more force.  If I were to create an experiment, I would go in with that hypothesis.  Could be wrong.

This sounds a bit like one of my childhood experiments, but you can take leaf spring from a truck then make a giant crossbow with it. A steel cable can be used for the string and a 3/4" steel rod can be used as a bolt you can couple with the cable. Then weld a 1/4" to 1/2" plate on the end where it impacts the golf ball at a slight angle to simulate loft. You can use a SS radar to measure the velocity.

I suppose you can make an adapter to hold a club on the end as well then tune the system to  produce a 100mph to 300mph golf ball? If you really fine tune it, you should be able to get 500-600 feet/second for at least 1-2" throw at peak velocity?

[RussUK]

22 hours ago, iacas said:

That's fine, but at the same time… you do realize who Phil Cheetham is, yes?

I'm all for questioning "experts" but I'm pretty cautious with some. Especially if I don't have much to go on.

I think your disagreement is simply a matter of definitions or context.

Very little power comes from the active use of your wrist muscles to snap the clubhead into the ball.

A substantial amount of speed comes from the angles of the wrist doing what they do, somewhat passively, to hit the ball.

Obviously that amount varies by the type of shot (a driver was used in these tests to get these percentages). For example, in a chip shot you could actively use the wrists to generate speed. And with a driver, I have little doubt that some long drive guys use their wrists a little bit. You and I? Probably less. But the angle still comes out, and it still directly contributes to clubhead speed.

So I think you're just off in how they're saying the "wrists" contribute. They aren't saying you actively fire the wrist muscles. I think they're just talking about the angle coming out - for example, if you made a swing where you actively tried to keep the wrist straight (no hinging, cocking, rolling, etc.).

Your arms moving across your body generate most of the clubhead speed (this includes the wrists doing what they do, too, and the forearms). Most of the power in the golf swing comes from your arms. See the post above @SavvySwede quoted.

I fairly firmly believe this to be accurate, as we've worked with Ph.D.s to arrive at that conclusion.

That doesn't really happen. You're seeing a result, not a cause. Just like my "coil" post in Swing Thoughts, if you suddenly stopped all motion of your torso in the downswing, you'd lose clubhead speed, not increase it. There's little conservation of angular momentum in the golf swing.

Here's a fairly good kinematic sequence.

It shows the pelvis (red), upper body (green), and the hands (blue) accelerating on the downswing in sequence. This has more to do with simply firing the right muscles at the right times, and with ranges of motion - many players can't really keep opening their hips at that rate where it peaks because they've reached the end of their range of motion (but that range then keeps getting extended because the torso keeps catching up).

It's possible to have a graph that doesn't look like this, too - it's possible to have hand speed peak at the wrong time, BEFORE the hips slow down, or the torso. They don't contribute much to the distal segment. Them slowing down also, really, slows down the segment they're attached to.

Your muscles are firing to do all of these things, particularly your arms and chest to move the arms across your body and into the ball.

The rotational aspect of the golf swing adds less than half of the speed in the golf swing. 20-25% or so. Try it - make a swing where you just rotate (don't use any vertical GRF either). Hold both of your arms really straight so you can't use them at all. Ball's not going very far.

Now, what it feels like to someone, well, that may be totally different. They may feel a "whip like" action though there isn't really one.

Not really what's happening. Many of them are at the edge of their range of motion at that moment in time. They're also doing some other things - the vertical GRF spikes from A6 to A7, for example, and that puts different forces and stresses and motions into play.

Rory has always been long, even when he was a bit doughy. He's said he's building up his muscles as injury prevention, because he's had degenerative disc stuff already, not so much to gain speed. He's always hit the ball far, even before he was working out like he is now.

Again, yeah, I don't think that's what Phil Cheetham is saying.

Plus, the players DO actively move their arms across their chests. Absolutely they do.

Let's get past quoting good golfers and look at the actual science, eh? We can do that these days.

Of course they generate quite a bit of speed. This video shows the legs being taken out of it, and almost all rotation being taken out of the golf swing. Dave is able to generate 70% or so of his normal clubhead speed… just by swinging his arms.

Many of the "alternative" swing methods seem to focus on arm swings (with little lower body movement), Joe Davidsons Symple Swing springs (horribly) to mind. Now, how much of an effect would even a small move towards the target and hip rotation have on he overall speed (a rough guestimate)?

P.s. Think Dave could be onto something with the "relaxed" golf. Size of chair may be an issue 

[Lihu]

3 hours ago, RussUK said:

Many of the "alternative" swing methods seem to focus on arm swings (with little lower body movement), Joe Davidsons Symple Swing springs (horribly) to mind. Now, how much of an effect would even a small move towards the target and hip rotation have on he overall speed (a rough guestimate)?

P.s. Think Dave could be onto something with the "relaxed" golf. Size of chair may be an issue 

I don't think this is an easy question to answer. The little lower body movement stuff just sounds wrong. Unless you have a disability, moving the lower body properly is essential to your swing.

Also, let's say your kinematic sequence is totally wrong, then moving the hips could even detract from the speed. Once your body is moving with proper sequencing, then all this stuff probably makes a difference. Until you get the first two keys reasonably (5SK), the rest of this stuff is pretty meaningless.

[iacas]

So, @Marty2019, how about that? Thoughts?