U.S. Open 2019: What’s Rory McIlroy wearing on his wrist?

PEBBLE BEACH, Calif. — Rory McIlroy has long been an example of the modern golf athlete; he relishes spending time in the gym maintaining the physique that allows him to keep up with the longest players in the world.

Recently, McIlroy has added something to his wellness arsenal: a wearable wristband called a WHOOP. What is a WHOOP, exactly? Essentially, it’s a wearable device that analyzes strain, recovery and sleep on an athlete’s body.

McIlroy was first spotted wearing his the device at this year’s Memorial Tournament.

👀 https://t.co/LWQtA3dEzc

— WHOOP (@WHOOP) May 28, 2019

At Memorial, McIlroy was spotted conversing with longtime WHOOP user Scott Stallings about wearing the device while playing. Stallings confirmed to GOLF.com that a number of players on Tour have been testing the device. Stallings has become among golf’s fittest players, too, after losing 50 pounds over the course of a year.

The only trouble with devices like the WHOOP is that the speedy motion of a golf swing can throw off measurements. But the benefits are wide-ranging. Stallings himself attests to getting more deep sleep, recovering better and ensuring that he works out on a more regular and efficient schedule.

As for McIlroy? Correlation is hard to prove, but in McIlroy’s first week with the WHOOP, he missed the cut at Memorial. The next week, at the RBC Canadian Open, something definitely worked. He blitzed the field, shot a final-round 61 and won by seven shots.

A number of other top athletes have utilized WHOOP’s services in recent years. NBA players, NFL players and MLB players are among those who have increasingly tracked their own movement to make their workout and recovery more efficient.

McIlroy has long defended golf workouts as a logical move in the game’s shift to the modern era. He even revealed his bench press on The Dan Patrick Show in 2018 — 250 pounds.

“I’m not as strong as I look,” McIlroy said with a laugh. “I’m sorry to disappoint you.”

Whatever he’s doing at Pebble Beach is working, too: McIlroy is T4 heading into Saturday’s third round.