It would be true for me to say that a pendulum on a grandfather clock has a good tempo, rhythm & timing and is also very predictable once in motion swinging freely back and forth with no interruption. So what would happen if i put my finger in the way of the pendulum???
It would stop the free swinging motion and affect the tempo, rhythm & timing.
Tempo, rhythm & timing come from a good body pivot, this produces a free swinging motion of the arms and club just like the pendulum. If you don't pivot your body correctly, your body will be in the way of your arms causing your arms to wrap/collapse around your body also known as Chicken Wing!!
This is a great picture of Jack Nicklaus, you can see how he pivots his body and the arms and club swing like a pendulum. If you turn your body out of the way on the backswing this will give you width preventing your left arm collapsing and on the downswing if you turn your body out of the way your arms will extend. No chicken wings doing it this way!!
Good Luck ;-)