Collision!

Few golfers are aware of what really happens when a clubhead collides with a golf ball at high speed, not to mention how much an off-center collision can effect the flight of the ball. My hope is that this article and the accompanying video footage will give each of you a much better understanding of the importance of solid contact. I would encourage you to watch the following PGATour.com video a few times...

 

As you can see a strike away from the center of gravity of the clubhead will lead to twisting of the clubhead. While most of the twisting occurs after impact, a portion of it does occur during the impact interval. It is this twisting during impact that leads to gear effect which can greatly alter the flight of a shot.

An off-center collision will twist the clubface in any direction.

A hit high on the face will tilt the face upward and reduce the amount of spin on the ball, while a low strike point will deloft the face and increase spin rate. A strike towards the toe will open the clubface and increase draw or reduce fade and a strike towards the heel will close the face and increase fade or reduce draw. Interestingly, the clubface will tilt vertically (top/bottom) almost as much as it will horizontally (toe/heel).

There are seven shots in the video and if each of them had a neutral club face and club path during impact, the results of each shot due to gear effect would have been as follows:

Shot 1 - A strike above the "equator" of the clubface and slightly towards the toe. Ideal if you would like to hit high launching, low spinning, draws that go a long way.

A High Toe Strike
A High Toe Strike

Shot 2 - A more pronounced high, toe side strike. This strike point is too far from aligning with the center of gravity of the clubhead to be beneficial. This flight due to gear effect would have been fairly high launching, low spinning and would not have faded as much as it might have appeared.

Shot 3 - Another extreme high, toe side strike along with a heavy descending blow - not good. High and right, but a fairly straight flight.

A Low Heel Side Strike
A Low Heel Side Strike

Shot 4 - A severely off-center hit where the collision is with a very low portion of the face and in the heel. Believe it or not this ball gets airborne and will almost always be an unimpressive high spinning,  low fade with very little distance.

Shot 5 - Charley Hoffman: I have seen numerous clips of high speed driver footage like this and I don't think I have ever seen one where I cannot detect any twisting at all. A slight downward attack angle. Appears to be very close to a perfect center of gravity strike - a truly rare event! Very straight.

Shot 6 - Matt Kuchar: A neutral attack angle along with a high, toe side strike. High launch, lower spin and a slight draw - boom!

Shot 7 - Luke Donald: About as solid as Charley Hoffman's shot, but the interesting thing about this clip is the attack angle - quite severely down. Solid and straight, but not optimal for maximum distance.

It is interesting to note that today's larger clubheads will resist twisting due to having a higher moment of inertia. MOI is a measure of a body’s resistance to angular acceleration or twisting. MOI really comes into play when the ball and the clubface meet someplace other than the sweet spot. The MOI of a club is higher for heel/toe mishits than it is for high/low mishits and therefore tends to be more forgiving on heel/toe mishits. However, golfers tend to mishit a shot further towards the heel/toe than they do high/low so the clubheads' resistance to twisting tends to even out.

Please know that physics is not selective and any golfer, pro or amateur, can hit any shot solidly or severely off-center. Also - no golfer can "stabilize" the clubface during or after impact due to an off-center strike.

This article shows you which part of the clubface is best.

I love this video footage and from here on out it will be required viewing for all my long term and golf school students. Would love to hear your thoughts....

Compress the Golf Ball

One of the most important aspects of great ball striking is compressing the golf ball. Now, we've all heard that statement and we know the feel of a purely struck shot, but what really is compression and how can we do a better job with it? Let's start by understanding the photograph below. This is a simulated shot where the clubface is just about to reach the back of the golf ball. The red line indicates where the loft or upward face angle is at impact and the blue line indicates the direction the clubhead is travelling during impact. The white line connecting the two represents the amount of compression "experienced" by the golf ball.

The narrower the gap or closer the two lines are the more compression will be exerted onto the golf ball and assuming a decent strike and appropriate launch, the ball will travel further. TrackMan refers to this gap as spin loft and without being too detailed it is the difference between where the face points at impact and where the clubhead travels at impact.

Fredrik Tuxen - one of the founders of TrackMan refers to spin loft as compression itself. To get a better understanding of how the numbers work let me give you a few examples: Jack hits a 5 iron with the face pointing at 16 degrees and the clubhead moving 2 degrees down. Bob swings at the same speed as Jack with his 5 iron and he gets the face pointing 15 degrees up and the clubhead moving 6 degrees down. Jack has a spin loft of 18 and Bob has a spin loft of 21. Both shots are hit well, so which goes further? Jack's does because he has a narrower spin loft gap and thus compresses the ball more than Bob. What spin loft would create the maximum compression? Zero! However, as we will learn spin loft is in large part responsible for the amount of spin imparted on any shot and a golf ball needs some spin to keep it flying in the air. I have found that a spin loft of 11 is very good for a driver.

Some interesting points about compression or spin loft:

  • Hitting down will not increase your compression of the golf ball or the spin on the shot. Invariably this only leads to a shot where the face angle and the clubhead direction both move downward - there is no change in spin or increase in distance.
  • A higher spin loft increases spin and generally slows down ball speed.
  • If you have similar swing speed, but hit your shots far shorter than your playing partners - this is due to a lack of compression on your shots.
  • Shots with a lower spin loft will curve in the air more easily than shots with less compression. That's why it's easier to keep a 7 iron straighter than a driver.
  • Custom club fitting can help to improve your spin loft simply by delofting either your irons or driver.

Now that we really understand what true compression is we can start to look at methods to help us improve our own ball striking. There are two ways we can compress the ball better - deloft the face angle more at impact without hitting down any more or hit down less without increasing the the loft of the face during impact. Ideally we need to deloft the face without hitting down any more. Notice how in the Jack and Bob example I used above - Bob's face was delofted more than Jack's, yet he hit down more and this limited his ability to compress the ball.

To get a good sense of what is required:

  • Get in front of a mirror with a 7 iron.
  • Grip the club and facing the mirror get the clubhead about 3" off the ground two feet back from where the ball would be.
  • Now slowly glide the clubhead through impact while maintaining the 3" space between the clubhead and the ground noticing that as you go beyond impact how much your hands need to stay in front.
  • When you start hitting balls - start small and hit soft shots off of a tee.
  • There should be no ground contact, try to leave the tee in the ground and see how low you can hit these little 7 iron shots.

This is the feel you want! Delofting the face without slamming the club into the ground. And believe it or not this applies to the driver as well. I know it may sound strange and it took me a while to wrap my brain around this, but it is entirely possible to hit up on the ball with the handle/hands in front of the clubhead.

If you have gained something from this article please share it with a friend. Let's be honest, they could most probably do with the help....

Understanding Swing Plane and Club Path

There are important differences that occur at impact when a golfer hits either down or up on the ball (attack angle).  I have always espoused that golfers hit down on all clubs, the driver included, but my research with Trackman has convinced me otherwise.  The ball should be struck with a subtle downward blow with all shots off the ground (irons, hybrids and fairways), but the driver should ideally be hit with an upward strike for optimal trajectory and spin patterns.  I will attempt to explain the differences in the direction the clubhead travels (relative to the target line) as it moves both down, and up, into the ball.

Firstly, it is important to understand the difference between swing plane (also referred to as swing direction) and club path, because too many golfers believe they are one and the same.  Let's view swing plane as the hula hoop in the pictures below - it is the angle upon which the arc of the swing travels.  Club path is the direction the clubhead is travelling in, relative to the target line, at the moment of impact.

Hitting down on the Ball:

 

PGA Tour golfers hit down on a 7 iron with an average attack angle of slightly more than 4 degrees.  You should be able to tell to what degree you hit down on the ball simply by analyzing your divots - too much dirt being moved and you're more than likely 8 degrees down, no divots would mean a flat or neutral attack angle.

When a golfer hits down on the ball with a neutral swing plane (straight at the target) notice how the pencil (used to illustrate club path) points right of the target. The table's edge indicates the target line.

Hitting down...

Down with a neutral plane...

This means that with a straight plane/swing direction, when the clubhead travels down, it is also travelling from in to out relative to the target line.

Left swing plane for neutral path...

In order to neutralize the club path, the swing plane must actually be rotated to the left.  Thus, with a descending attack angle, in order to create a straight club path, the swing plane must be rotated to the left of the target line (for right handers).

Hitting up on the Ball:

 

Better drivers of the ball tend to hit up on the ball - anywhere from 1-5 degrees up.  This reduces the amount of spin on the ball and increases the launch angle - thus increasing both carry and roll distance.

When a golfer hits up on the ball with a neutral swing plane (straight at the target) notice how the pencil (club path) points left of the target. 

In this example, with a straight plane/swing direction, when the clubhead travels upward, it is also travelling from out to in relative to the target line

This out to in path can be neutralized by rotating the swing plane/direction to the right (for right handers).  Notice how the pencil (club path) is now straight.

So if somebody ever asks you if the swing with the driver and the irons is the same, just smile and say, "No, not really!"

Any thoughts?  Questions....