What is AimPoint Express? And why are so many PGA Tour pros using the green reading system?

Surprisingly, the creator said, developing this skill is easy.

Eight-foot putts are not typically stressful for PGA Tour pros, but the 8-foot par putt that Max Homa faced on Friday morning on the fifth at Augusta National had to be made if he was going to stay tied for the lead at the 2024 Masters. On the outside, he looked calm, but on the inside, he had to be feeling the pressure.

After both Tiger Woods and Jason Day finished the hole, the dance floor was Homa’s. With one foot on either side of his golf ball, he bent his right arm at about a 90-degree angle and held up his index finger and middle finger while staring at the hole. After backing up four paces, bending to take another look toward the hole, and then getting into his address position, Homa set his putter behind the ball. No practice strokes. He made a quick glance toward the cup, made his stroke and buried the putt.

“I mean, that is special,” said Colt Knost on the ESPN+ broadcast before Billy Ray Brown added, “That’s what champions do.”

Max Homa
Max Homa lines up a putt on the no. 9 green during the second round of the Masters Tournament. Mandatory Credit: Adam Cairns-USA TODAY Network

But what was Homa doing with his fingers, which appeared to be what Will Zalatoris, Viktor Hovland, Keegan Bradley, Tommy Fleetwood, Collin Morikawa, Adam Scott and a growing number of other PGA Tour pros are doing? Like those other pros, Homa uses AimPoint Express. This green-reading technique was developed by Mark Sweeney, the man who created the AimPoint putting line that broadcasters like Golf Channel, NBC and CBS used to show viewers a virtual path a ball needed to travel to finish in the hole.

“AimPoint Express is a dramatic simplification of what is a very complicated computer program to figure out how the ball goes from Point A to Point B and goes into the hole,” Sweeney said. “AimPoint Express takes about 100,000 lines of code and converts it into the player feeling how much side tilt there is in the putt.”

What television viewers did not see during the broadcast of Homa’s putt on the fifth hole was that he had not only straddled his golf ball before he putted, but that he also stood halfway between his golf ball and the hole for a few seconds and tried to feel the tilt of the putting surface. Through practice and some training, Homa and other golfers can feel the difference between a one-, two- and three-percent slope to one side or another using their feet.

Then, standing over their golf ball, they extend an arm and hold up the number of figures that correspond to the estimated number of degrees in the tilt they felt — one finger for a one-percent slope, two fingers for a two-percent slope and so on.

Viktor Hovland and Will Zalatoris
Viktor Hovland and Will Zalatoris both use AimPoint Express. (Adam Cairns-USA TODAY Sports)

Sweeney accidentally discovered the relationship between the slope of a green, the length of a golfer’s arm and the width of a person’s fingers.

“I had a much more complicated method of reading greens prior to AimPoint Express,” said Sweeney. “But then I was teaching some young kids, 7- and 8-year-olds, and I had them put their thumb on the high side of the hole, just to get them aiming somewhere above the hole. It turns out that your thumb is perfect for one’s and two’s, it will get you close, but then we started experimenting with one finger per percent. We tested those reads against the math and it was insane how accurate it was. Like, it was within an inch or two every single time (from 20 feet).”

Knowing that, and seeing Homa on the fifth hole holding up two fingers, viewers familiar with AimPoint Express would know that Max was estimating that halfway to the hole, there was a two-perfect tilt in the green. From Homa’s perspective, his target on that putt was two fingers’ width to the right of the hole (probably about 4 inches right), and assuming he hit the putt directly at that target, he was right because the ball went in the cup.

Every week, pros can be seen practicing AimPoint Express and developing their sense of feel for slopes on the practice greens at PGA Tour events. Many of them bring a digital level, and as they stand along an intended putt line, they call out a slope percentage like one, two or three while their caddy looks at the level.

Surprisingly, Sweeney said, developing this skill is easy.

“Within about 15 minutes, most people are picking up half-degrees of slope,” he said. “People are much, much better at feeling slope than they think. Nobody is ever off by more than one percent. Like, it’s almost unheard of that a player is off by more than one percent. No one calls a one a three or a one a four because they are so dramatically different.”

Ben An
Ben An doing slope detection exercises with his caddie at Riviera Country Club. (David Dusek/Golfweek)

Sweeney claims that anybody, with a bit of practice, can accurately estimate to a half-percent. He also encourages golfers to calculate the slope along their putt’s length twice around halfway between the ball and the hole and use the bigger of the two estimations for their read. Some players, like Homa, take one reading and then turn around and repeat the estimation facing toward the ball to confirm their first reading.

In a Golf Channel interview, Homa said, “Your eyes can lie to you a lot, but your feet, typically, will never lie.”

Tiger Woods does not use AimPoint Express, and neither does Jordan Spieth or Jason Day. Brad Faxon, Loren Roberts and Ben Crenshaw never used it either. Some golfers have a great feel for green reading, spotting slopes and contours on the putting surface and understanding how putts will roll. However, many golfers are not blessed with this ability. Sweeney hates hearing that the skill will come with time and experience.

“As a coach, you have to take someone who doesn’t have a skill and give them that skill,” said Sweeney, who works with several tour pros and teaches lessons at Waldorf Astoria Golf Club in Orlando, Florida. “How do you teach someone green reading if they don’t naturally see what a good green reader sees? I thought ‘Just go do it and you’ll get better,’ was a really crappy answer. It’s like a full-swing instructor saying to someone, ‘I know you’re slicing it off the tee, but just go hit a lot of balls and you’ll get better.'”

Tom Kim
Tom Kim and his caddie practice reading greens with a digital level before the start of the Genesis Invitational. (David Dusek/Golfweek)

Aimpoint Express removes the need to walk around a hole and see your intended putt from multiple angles, so for Sweeney, it does not slow play as some people think.

Sweeney postulates that the better a golfer gets at reading greens, the more time they can spend working on improving distance control and developing the quality of their putting stroke.

“It’s really helped me to read the greens, obviously, but it’s turned a lot of that into better speed,” Homa said on Golf Channel. “I’m shocked more people don’t do it, if I am being honest.”

Looking for a true test of skill and nerve? Throw away the green-reading book.

Getting a small ball to disappear down a hole has been the bane of many a golfing life through the ages.

Have you ever had a read at some of the stuff cobbled together by the Global Odds Index?

It’s an organization that examines all sorts of probabilities in life, from winning the lottery or getting struck by lightning to the chances of you understanding what the Dickens I’m prattling on about in my column.

According to findings in the latest study by the Global whatstheirchops, the odds of a Brazilian male becoming a professional golfer are 1 in 7.7 million.

About the same, then, of a reader – yes, a reader like you with that increasingly glazed look – getting to the bottom of this ruddy page. So, let’s crack on. The odds are stacked against us. We’ll start with green-reading books.

Watching certain modern-day professionals examining the line of a putt with one of those highly detailed compendiums is broadly equivalent to peering at someone scrutinising a particularly intrepid diagram of techniques in the Kama Sutra.

They’ll study the myriad slopes, curves, and borrows of the putting surface while contorting themselves into various positions for a better view during an elaborate and tiresome process which often ends in the sighing, eye-rolling anti-climax of it being left woefully short. Now, there’s a colourful description of a tricky 15-footer that really should be read after the watershed.

Recently, golf’s governing bodies, the R&A and USGA, unveiled a Model Local Rule to further reduce the use of green-reading paraphernalia at the highest level of competitive golf.

The rule MLR G-11, which admittedly looks like a personalised number plate you’d see on a swanky car parked outside the R&A clubhouse, will, as of January 1 2022, enable a committee to establish an officially approved yardage book for a competition so that the diagrams of greens show only minimal detail.

In addition, the local rule limits the handwritten notes that players and caddies are allowed to add to the approved yardage book.

The purpose? “To ensure that players and caddies use only their eyes and feel to help them read the line of play on the putting green.”

Now there’s a novel idea.

Getting a small ball to disappear down a hole has been the bane of many a golfing life through the ages. The mighty Old Tom Morris, for instance, was so renowned for his putting woes, a letter sent back in the day simply addressed ‘The Misser of Short Putts, Prestwick’ was delivered straight to him by the postman.

And what was it Tony Lema once uttered about the putter? “Here is an instrument of torture, designed by Tantalus and forged in the devil’s own smithy.”

Putting has always been the ultimate test of nerve and skill. For those of us of a more old-fangled approach, watching golfers consulting some kind of Ordnance Survey map on the green while embroiled in an extravagant, time-consuming pre-putt routine that resembles the complex mating rituals of the Greater sage Grouse tends to grind the teeth.

In an age when craft, feel and instinct can be sacrificed on the altar of advancements in aids and accoutrements, players will always use something or other in an effort to gain an advantage if someone else is using the same something or other.

The more that’s available, the more they’ll add to the armoury. It’s in a golfer’s nature. On a slight detour from the topic, I remember nipping along one year to a World Hickory Open at Craigielaw and some of Scotland’s up-and-coming pros and amateurs who were competing revelled in the opportunity of playing with just five clubs and no assistance from strokesavers, course guides or any other visual aids. The senses were roused and they relied on sheer golf intuition.

Amid the general clutter of thoughts and processes than can make this such a mind-mangling game, sometimes less is more.

As for these green books? “I use a green book, but I’d like to get rid of them,” admitted Rory McIlroy earlier in the season. “For the greater good of the game, I’d like to see them outlawed and for them not to be used anymore.”
McIlroy, and others, may get their wish.

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USGA, R&A introduce rule that limits use of green-reading materials

The local rule even limits the handwritten notes players and caddies are allowed to add to approved yardage books.

PGA Tour players received a memo last month that explained how new rules governing the use of yardage books could be going into effect soon. The proposed Model Local Rule (MLR) aimed to reduce players’ dependency on green-reading books that often look like highly-detailed topographic maps and emphasize the skill of judging slopes, ridges, and breaks with your eyes and experience.

On Wednesday, the R&A and USGA jointly announced the creation of MLR G-11, a new mechanism that lets tournament committees require golfers and caddies to use only tournament-approved yardage books. The new MLR also severely limits what players and caddies can write or add to those books.

The R&A and USGA stated MLR G-11, which can be used starting on Jan. 1, 2022, is meant to be used at the highest levels of golf like the PGA Tour, European Tour, LPGA and Korn Ferry Tour. This is not intended to be used at recreational events or local golf tournaments. In other words, you will still be able to use old yardage books at next year’s member-guest and club championship, but Bryson DeChambeau will not be able to work with as much data in his yardage book at the 2022 Farmers Insurance Open or U.S. Open.

Specifically, MLR G-11 will require that all players and caddies use a yardage book that is not larger than 7 inches by 4.25 inches in size, and the scale of the greens can not exceed 3/8 of an inch for every 5 yards. Unlike many modern yardage books that show every the most gentle contour and slopes, the books approved when MLR G-11 is in effect can only show significant tiers, slopes and false edges.

After players and caddies get their approved yardage book, they will be limited with regard to what they can add to it before and during rounds. Club distances are fine, and they can make notes about putts they see either in person or on television. However, a player or caddie can not use a level or slope-measuring device during a practice round and then add information to the book. They also can not add any information gathered by other people.

The R&A and USGA leave players and caddies no wiggle room. In the statement, they wrote, “Handwritten notes must be based on the player’s or caddie’s experiences or observations of a ball rolling on a green, or through the player’s or caddie’s feel or general observations of the green.”

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The details included in modern yardage books have been criticized for not only removing skill from a player’s performance on the greens but also for adding to the slow-play problems at elite events.

Among the critics is Rory McIlroy, who has said they should be banned. Before the start of the 2021 U.S. open, he said, “I use a green book and I’d like to get rid of them.” He then added, “Most guys on tour are in the same boat that if it is available and if it’s going to help us, people are going to use it. But I think, for the greater good of the game, I’d like to see them be outlawed and not to be used anymore.”

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