I was giving a lesson last week to a student who was not following through and finishing her swing.
I demonstrated what a good finish should look like with the hips fully rotated so that the torso faced the target with the weight transferred to the forward leg. I also pointed out that the arm swing was completed as well, with the club over my forward shoulder and then asked her to imitate me.
After taking a few practice swings doing this, I then had her hit a ball and she immediately went back to her old habit of not following through.
The next step was to ask her to repeat the practice swings and hold her finish position for a count to 2 (we call this the TV finish because tour professionals frequently finish their swings and watch the progress of their shot while still in this position). Then I asked her to hit a ball and do the same thing, follow all the way through and hold her finish position for 2 seconds. http://www.youtube.com/watch?v=3PXpVT6g2LU
She did this a few times and then questioned me on why did the follow through matter as she had already hit the ball.
The answer is simple. By not committing to finishing the swing, she was actually de-accelerating at impact, and her left arm was collapsing prior to impact (remember last week’s article on the most important moment in the golf swing, impact, and the need to have the left arm fully extended with the club in line with it).
Her weight was not fully transferring and her hips did not rotate around to face the target. She could not achieve a solid hit on the center of the clubface because of this. She was also losing a lot of club-head speed and therefore distance.
I believe this is a common misconception, that the follow through does not matter because you have already hit the ball, not only in the full swing but on all of the short game shots as well. I certainly see many instances where on chips and putts, there is all back-swing and no follow-through.
A comparison would be in football, when the quarterback does not have a chance to step into his delivery and follow-through because of defensive pressure. The result is usually not good, with an incompletion or even an interception the result.
Improve your game by committing to following through.