Putting: The Pendulum Stroke

I want to dispel a few myths around the putting stroke, change some of your thoughts about it, and help you make a few more putts.

If you really understand pendulums, then you know that the following three common pieces of golf advice cannot all be true.

• The putting stroke should be a pure pendulum motion
• When you putt, you should accelerate through the ball
• You should hit the putt on the upswing of your stroke

The astute will realize that you can make any two of these statements true, and the third must be false. You cannot have all three. Let’s examine why.

What is a pendulum?

A pendulum is a weight hung from a fixed point. The weight swings back and forth from this point, acted upon by gravity. This set of conditions leads to some interesting results.

First, regardless of how far a pendulum swings, the period of time between its two highest points is the same. It may only swing a few inches, it may swing a few feet, so long as the anchor point does not change, then the period of time elapsed when traveling between these two points is the same.

As this applies to putting, your stroke should take roughly the same time from the end of the backswing to the end of the foreswing regardless of how long of a stroke you take. Could be a tap in, could be a 50 footer. The timing is the same.

Second, because a pendulum is only acted on by gravity, it has some intriguing properties in regards to velocity and acceleration. Let me remind you of the meaning of these terms since it may have been quite some time since high school physics for you:

• “Velocity” is the speed at which an object travels. It is the change of distance over time, hence, miles per hour, feet per second, etc.
• ”Acceleration” is the change in velocity over time. An object can accelerate, that is, gain speed over a period of time, or decelerate, lose speed over time.

With a pendulum, the hung weight accelerates and decelerates as the force of gravity acts upon it. As the weight swings downward towards the bottom of the arc, it accelerates as gravity pulls it downward. Yet, as soon as the weight begins to travel upwards, it is decelerating, as gravity fights against the forces pulling the weight upwards.

So what is the acceleration of the weight when it’s precisely at the bottom of its arc?

I’ll give you a moment to think about it.

It’s 0. There is no acceleration. There is no change in velocity.

At the bottom of its arc, a pendulum is at its greatest velocity. It is traveling at the fastest speed it will go, but it has no change in that speed (for that infinitesimally brief moment).

As this applies to putting, you can begin to see how reconciling those three pieces of advice from before is impossible. If you make “pure pendulum stroke” and “accelerate through the ball” true, then you have to hit the ball on the downswing of the stroke, before the putter head reaches the bottom of its arc.

If you try to make “accelerate through the ball” and “hit the ball on the upswing” true, then you can’t have a pure pendulum motion. You have to introduce acceleration into the putter head on its way up with hand/arm/shoulder/body manipulation. For what it’s worth, most people choose this option. They take too short a backswing, rush the putter head through the ball, and have absolutely awful speed control because of it.

I think you should choose to make a “pure pendulum stroke” and “hit the ball on the upswing” both true. Let me try and convince you.

The third option

If you choose this third option, then the natural conclusion is that the putter head is decelerating at the point of contact with the ball. This probably fills you with a bit of dread.

Almost all golfers have experienced the awful “quitting on it” putting stroke. It’s a stroke made with fear or indecision where the hands actively slow the putter head down as it approaches the ball, producing a weak and inadequate roll. Absolutely no one likes making this stroke. It literally feels awful at contact.

But the keyword in that last paragraph is “actively”. The “quitting” stroke comes from active manipulation of the putter. I promise, if you make a pure pendulum stroke, you won’t even notice that the club head is slowing down at impact. You can make solid, affirmative contact because the putter head will still have plenty of velocity.

Personally, I think “accelerate through the ball” should also fill you with dread, as it is also only achieved through active manipulation of the putter head. Actively increasing the putter head’s velocity through the ball means adding force via the hands, forearms, shoulders or somewhere else in the body. These additional forces can cause us to have poor speed management or starting line control. So it can also be bad.

What we want is a putter that freely falls from the end of the backstroke to the end of the forwardstroke, just as the pendulum weight swings on its arc. The keyword there is “freely”.

We want gravity to supply the force that creates acceleration leading up to impact, and we want gravity to bring our putting stroke gently to a stop at the end. Our hands and arms simply supply a connection to the fixed anchor point of our putting stroke.

Instead of thinking about the stroke as accelerating the putter through the ball, I believe it is better to think of the stroke as an act of “gathering energy” and letting gravity apply that energy to the ball.

We swing the putter back on its arc so that it can gain energy to transfer to the ball. When we have a longer putt, we want to swing the putter (smoothly) with more energy to achieve a longer stroke, just as a pendulum would swing with more velocity to a higher point on its arc.

At the top of the putting stroke, the putter head should feel full of energy. The weight of the putter primed with force to hit the ball at the speed you want to make the putt. From here, you’re only job is to stay out of the way of the putter head. Let it flow through the ball, coming naturally to its conclusion at the end of the stroke.

Coasting

So we don’t want to actively accelerate or decelerate through the ball. Is there a feeling or metaphor we can use to describe how the putter should feel in the impact zone? I think so.

If you’ve ever driven a car on a flat road, how does it feel when you take your foot off the gas, but don’t put it on the brake. The car just kind of… coasts. Or if you’re not old enough to drive, perhaps you’ve ridden a bicycle and stopped pedaling for a bit. The bike just glides on the smooth surface for a while. The speed doesn’t last forever. Eventually friction slows you down, but there’s a period of time where you’re coasting on by. Without manipulation. Just freely flowing.

This is how we want the putter to feel. That it’s just coasting through the ball. Gather speed and energy in the putter head going back, let it freely fall going forward, and coast at impact. Enjoy the ride.

A putter to study

I think everyone should go study Patrick Cantlay’s putting stroke to get a better understanding of what I’m talking about.

Cantlay is not afraid to take as long a backswing as he needs to gather energy for the putt. Don’t believe me, watch this clip of him shooting 66 at the BMW Championship in 2021 and making a huge pressure putt on the 72nd hole to force a playoff he would go on to win. Watch him make these pressure putts, see how long his stroke is. I bet his backswing is twice as long as yours for some of those distances. And remember, they’re playing on fast greens.

He also does an excellent job of applying no forces other than gravity to the putter as it swings freely back into the ball. His putting stroke really is about gathering energy going back and letting gravity apply it to the ball.

As long as his setup is consistent and correct, Cantlay has no reason to worry about pulling or pushing a putt. He isn’t actively doing any manipulation that could disrupt the clubhead and cause that to happen.

That’s a stroke worth emulating.