Impact Science: Ball Flight Laws

We hear it all the time. Impact is the moment of truth, the most important point in the golf swing. The only problem is that we have seen very little describing exactly what happens at impact.

The club and the ball are only touching each other for about 4/10,000th of a second! It is the only time that the ball gets instructions. So, if you shoot an 80 that is 320/10,000th of a second. Thus, 1/30th of one second determined your entire round of golf!

All of my articles will always tie into impact; you should only institute the swing changes that positively affect impact.

So, what are the components of a good impact? A good impact must include:

Alignments that produce the desired shot shape and distance;

  • It must be repeatable;
  • It must be repeatable without causing injury.

When analyzing a golf swing, the first question to ask is what shape and trajectory the golfer sees the ball going to the hole on their base shot.

I ask the student to imagine a hole with a 10,000 square foot green that is flat with the hole cut in the middle of the green, or a very wide fairway if they are hitting a driver. The conditions include: no wind, no bunkers, no hazards, no trees, no out of bounds, and you are hitting from the middle of the fairway from a perfect lie or on a tee.

After the shot shape is determined it is the instructors responsibility to have the equipment to measure impact components and the knowledge and expertise to adjust the student’s swing or equipment for the student to produce the desired impact alignments.

This is the origin of where teaching and game improvement starts. This exercise should also take place for specialty shots such as intentional draws, fades, etc…

What brought me to this conclusion? Impact physics laws. These laws are what control ball flight.

The 4 BALL FLIGHT components are:

  • Ball Speed
  • Launch Angle
  • Spin Rate
  • Spin Axis Tilt

Next are Impact Alignments. The 4 impact alignments that control the ball flight components above are what we commonly call the ball flight laws. I call them the club impact alignments that produce ball flight. There are only four of them. The instructor must master the understanding of them.


  • Club head speed at impact. This is the most important impact component for distance. Driver club head speed on the PGA Tour is around 112 miles per hour and on the LPGA Tour is about 95 miles per hour. You can gain about 2 to 3 yards for every mile per hour you can swing the club faster.
  • The club head path direction at impact. This combines the horizontal and vertical direction or path of the club head motion in relation to the target at the moment of impact. The vertical direction of the club through impact is also commonly called angle of attack or angle of approach. We combine the right and left direction and the up and down direction into one because the overall path of the club forms ½ of the D-Plane ball flight model.
  • The direction the club face is pointing at the moment of maximum compression during impact. One of the most important things to understand is that the leading edge of the club and the clubface are only pointing in the same direction if the lie of the club is correct at impact. For instance, if the ball is above your feet when the leading edge is pointing to the hole the clubface is pointing to the left. This is even more prevalent with more lofted clubs. The clubface direction at impact forms the other ½ of the D-Plane.
  • Impact location on the face. The location of the impact point on the face has a great affect of how much of the club head energy is transferred into the ball. The more solid the hit the faster the ball leaves the face and the more the club head is slowed by the impact collision.

a. For instance a driver club head speed of 100 miles per hour can produce a maximum of approximately 150 miles per hour of ball speed. Also, the impact point on the face has an effect on the trajectory and direction of the shot. The reason for this is because of what is called the gear effect.

b. Whenever the ball hits toward the heel and the toe or high or low on the clubface the club head twists. Especially when the center of gravity is back away from the face such as with a metal wood. Hybrids and some game improvement irons with wide soles also have center of gravities that are away from the face. Irons with little or no cavity back have virtually no gear effect.

So it is the four impact alignments (or ball flight laws) that produce the ball speed, launch angle, spin axis tilt and spin rate of each shot. The management of these 4 impact alignments is the prime reason to alter the swing or equipment. They must be measureable and adjustable.

2014-15 PGA Tour Dates


tweet tweet!