The 'golden' metric pros know—and the innovative training aid behind it

It's not often you'll see a training aid immediately sweep through the top ranks of professional golf. But that's what the ProSENDR training aid has done upon its launch earlier this year.

Co-founder David Woods doesn't see it stopping there.

"I want the ProSENDR to be as big as Trackman, where you see every player using it on the range before their round," Woods says. "It's another way of getting them dialed."

"I've been approached to do a lot of training aids over the years," adds co-founder, Golf Digest Top 50 Teacher Sean Foley. "I didn't want to do it until I found one I actually believed in."

The ProSENDR is that one Foley says, who explains that there's some good science behind it, too.

The 'golden' wrist range

The rise of 3D technology is helping golf instructors understand more about the mechanics of golf swings than ever before. Among the many other things they've learned is that pros' wrists work in very specific ways.

The trail wrist — which is the right hand for most right handed golfers — is an increasingly key focus. Hold your arms out in front with your palms towards the ground then bend your wrists towards you. You've just put your wrists into what's known as "extension." It's a crucial move within the golf swing, and pros operate within a pretty tight range.

"Pros generally have between 42 and 63 degrees of trail wrist extension between the backswing and downswing," Woods explains. "That's their range where they want to operate within."

When their wrist is in that range, it helps golfers do a number of important things, really well, Foley explains. It helps you release the club at the exact moment for maximum speed, and prevents your swing from moving too far from out-to-in, or in-to-out, which cause slices and hooks.

Of course, pros don't want to go into a tournament thinking about the exact number of degrees one of their wrists is extending. They want a feel they can put into play, which was the inspiration behind the training aid.

The ProSENDR looks a little like a wrist brace. Golfers wear it over their trail hand — right hand for right-handed golfers — and the shell is pitched just off the back of the trail hand. As they begin their swing, the golfer's hand will meet the shell; the goal of the golfer is to keep the two in contact during the early part of the downswing. If you do that, Woods explains, your swings will be within the same parameters as most pros.

Rory McIlroy was spotted using the device before his T-2 finish at the 2023 U.S. Open, along with Senior Open Championship Alex Cjeka and many other other pros.

Byeong Hun An, a student of Foley's, is one of those. He's been working on keeping his arms wider on the backswing, he says, and the ProSendr helps him do it.

"We're trying to stay in the middle range," An says. "I hit it a lot farther. I was about 172 [with a driver] before. Now it's about 180 to 182. That's about 10 yards of gain without me trying to hit it hard or anything, just making little swing changes. Golf is a lot easier when you can hit it farther."