From Robert D. Grober, a physics professor at Yale:
"It is shown that the putting stroke of world class golfers can be described as the motion of a pendulum driven at twice its natural resonance frequency. This model minimizes error in the speed of the putter head due to random errors in the magnitude of the applied forces, providing rational for why great players have developed this particular putting stroke."
Well said. We think.
Here's a more detailed story on his study, in Technology Review.
-- John Strege