In the previous parts of the Key Concepts series, we talked about hitting the ball first, then taking a divot. We also talked the alignments needed to create this consistent dynamics between the club, the ball and the ground.
In this part I want to discuss 'compression.' What is compression? Well lets take a look at this excellent definition from poster Jaridyard over at John Graham's Forum:
Compression is the deforming of the golf ball with the clubhead during the impact interval.Here's a video of a golf ball being compressed with a driver.
Maximum compression can be achieved by reducing the difference between attack angle and loft (ie A driver creates greater compression than a wedge). Compression is further maximized by minimizing the difference between path and face angle, minimal glancing blow.
To clear some of the other stuff Jaridyard stated, attack angle is the downward or upward angle the clubhead comes toward the ball at impact. The average attack angle for a PGA Tour player is -1*. Let's say the average loft on a PGA Tour driver is 9*, that's a difference of 10*.
The average 7-iron attack angle for a PGA Tour player is -4*. Let's say the average loft of a 7-iron is 34*, that's a difference of 38*. That's why the compression with a driver is greater than a 7-iron, the difference between attack angle and loft is less.
As far as minimizing the difference between clubface angle and clubpath, if my clubface angle is closed quite a bit, but my path is going out to the right quite a bit (inside-to-out), that will likely hurt my compression because I'm more likely to catch the ball of the toe of the clubface.
Here's the key concept between the way most golfers *think* and how good ballstrikers *think.*
Most golfers' goal when hitting a shot is more oriented towards getting the ball up in the air and hitting it relatively straight. Good ballstrikers think very differently. Their goal is more oriented towards compressing the golf ball and that will take care of not only getting the ball up into the air, but getting the right trajectory and usually keeps the ball relatively straight.