Get off the clock: In this tip, learn why accelerating works better than a pendulum
"Swing the putter like a pendulum" is one of those ageless pieces of advice we'd do better to ignore. While the concept of the pure swing of the pendulum is a seductive one, it rarely translates into improved putting performance.
For one thing, unless you're a machine, it is hard to achieve – Bobby Jones once described the pendulum stroke "a thing absolutely impossible of accomplishment so long as human beings are built as we know them". And second, it confers less control of the clubface. Here's what you should do instead.
Fault: Poor face control when trying the pendulum rhythm
Fix: Think 'pass' or 'kick' to feel the appropriate movement
The Issues with the Pendulum Rhythm
Low face value
To feel the weakness of the pendulum stroke, dangle your putter in front of you, pull it back and let it swing. With nothing but gravity powering it, little energy is created and the face becomes very unstable.
How to fix it using a simple drill
In a pendulum stroke the throughswing is as long as the backswing – a 1:1 ratio. Instead, turn this into a 2:1 feel, your throughswing doubling the length of your backswing. Practise this by using your trail foot instep as a guide for backswing length.
Follow through with brisk and firm motion, enough to send the putter's head twice as far through as you pulled it back. Note, how, with this assisted acceleration, the face feels more stable and more ready to stay square.
Keep it smooth
Acceleration does not mean your stroke has to become snappy or jerky. You can still use gravity to keep the putter's change of direction smooth; but once it has started forward, focus on striking firmly through the ball.
Practise this 2:1 length ratio until its rhythm starts to feel more natural and instinctive, getting used to how far the acceleration sends the ball. When the stroke feels familiar and comfortable, try it on the course.