The science of goaltending
How Sergei Bobrovsky and other elite goalies use their gaze
The quiet eye
A good way to test your visual perception is to look directly at your eyes in a mirror, first the left and then the right. Then back to the left. What you’ll notice is … well, nothing. You wont actually see your eyes moving. You can try this with your spouse, though, staring deeply into their eyes, which I definitely recommend if you really want to creep them out. But also what you will see is their eyes moving. From this, we know it’s happening.
Why can’t we see our own eyes moving?
Our visual perception system doesn’t allow us to. Our eyes are actually moving pretty much constantly. In addition to regular blinking to moisten the lens (or refresh the brain - hmm), our eyes do something called saccades. These are short, rapid shifts that occur about 4 to 5 times every second. They transpire so quickly that we generally don’t notice them. In fact, we suppress noticing them.
Our eyes are constantly scanning the scenes in an environment, whether it’s the words on this page, the cars on the highway, or the receivers on a football field. It’s most likely a defense mechanism we’ve evolved with. A fancy little trick also evolved along with it. See, even as our eyes are moving and scanning, we generally perceive most scenes as stable, thanks to the brain. During a saccade, it’s been hypothesized that we are effectively blinded. It’s only for a short duration, but the brain has to fill in those saccadic gaps 4 to 5 times every second. Our vision is essentially a story the brain is telling ourself.
Saccades also happen to be quite helpful for keeping track of things in a fast-moving sport. In honor of the Stanley Cup Finals starting tomorrow night, let’s consider a hockey goalie, for instance. Hockey is an incredibly frenetic activity in a small environment played on ice. To keep track of opponents and teammates and the tiny black puck that are all zooming around the rink, it would behoove a hockey goalie to be able to make short, rapid shifts of the eyes.
But when a goalie is preparing to face a prospective slap shot from an opponent, perhaps a rapid eye shift isn’t the best formula for success. Blindness doesn’t bode well for a strong save percentage.
So what is a Sergei Bobrovsky or Stuart Skinner actually doing with his eyes?
Train your gaze
The seminal study on hockey goaltending comes from two Canadian researchers (fittingly) at the University of Calgary in 2006. Their names are Joan Vickers and Derek Panchuk, her graduate student.
Panchuk and Vickers weren’t the first to examine eye movements in hockey goalies while they faced shots in a live setting. The first (Bard & Fleury, 1981) was a bit constrained technologically, but it found that expert goalies predominantly fixated their vision on the puck, rather than the shooter, to make saves — a fairly significant finding at the time (ie., keep your eyes on the ball).
To their credit, Panchuk and Vickers point out that a lot of shots in hockey transpire in less than two-tenths of a second, faster than the visual system can process. And yet goalies still save 90 percent of their shots. Not all of this is just luck.
In their study, Panchuk and Vickers gathered eight elite goaltenders from Canadian universities around Calgary and several elite shooters to feed them wrist shots from 5m and 10m out, distances at which the puck would travel below the threshold of human visual perception. They used an innovative wireless headset that was able to track both the goalie’s eyes as well as whatever target they were looking at simultaneously.
What they found was that the most successful goalies trained their gaze directly on the puck for as long as a full second before the shot was released. This direct focus was not broken at all prior to the onset of the saving movement.
I suppose this finding may sound fairly obvious — again, we’ve all heard “keep your eyes on the ball/puck.” But when testing novice goaltenders on the same task, Vickers and Panchuk discovered that their gaze was typically … all over the place. It was saccadic chaos. Elite performance requires the opposite.
Furthermore, Vickers and Panchuk have gone on to show that the quiet eye is critical for goalie performance even when the path of the puck can’t be predicted. More recently, they tested goalies’ gaze on shots that are deflected, putting fiberglass boards at an angle off the net to produce unexpected deviations in the puck’s flight path.
Again, they found that the goalies had the most success when they located the puck earlier and maintained their gaze on that location for longer, even for shots that they knew wouldn’t be straight. The “optimal” time to locate the puck was as much as 2 seconds before the shot’s release, and the “optimal” duration of that gaze went for 2-2.3 seconds—extending early into the shot’s flight.
That’s not to say the goalies didn’t try to follow the puck after the deflection, but most of the time their gaze simply arrived too late. But it didn’t matter. They were able to stop the shot with what’s become known as the Quiet Eye.
Origins of the Quiet Eye
By the time Vickers had started looking into hockey goaltending, she was already a monumental figure in the study of elite performance. She coined the term for what all this eye fixation business was about. She called it the Quiet Eye, and study after study going back to the early 1990s had confirmed its presence in expert putting, free-throw shooting, marksmanship, table tennis, volleyball returning, even surgical knot tying.
Before starting her PhD at the University of British Columbia, Vickers was an accomplished volleyball and basketball player, and then a coach and athletic director at several high schools and colleges. She traces her interest in sports perception back to a specific, high-pressure volleyball game in which she was serving. All she can remember is that, as the intensity grew, her focus magnified onto a specific back portion of the ball she was targeting to hit with the heel of her hand. The fine-tuning of this concentration should sound familiar to anyone who has lined up a putt, leaned in for a tennis serve, or readied a free throw.
I think there sometimes may be a tendency to conflate a Quiet Eye with focus or concentration, both of which are also necessary for performance in key moments.
Quiet eye, however, isn’t a manifestation of something psychological. It’s perceptual.
An important characteristic of this particular fixed gaze is that it is the last eye movement before the onset of the movement to block a puck or take a shot. This suggests that it plays a role in the planning of the movement. It’s not just “keep your eyes on the ball.” It’s, “keep your eyes on the ball in order to give your body the opportunity to hit it.”
Another noteworthy observation: Across Vickers’ 20+ years of research on this, she has consistently found that the Quiet Eye of elite performers is longer and started earlier than lower-skilled performers. In other words, this isn’t just about having superior vision — Vickers (to my knowledge) has never correlated an athlete’s 20/20 vision to Quiet Eye. Rather, elite performers find ways to see critical information sooner. And they fixate on that information for longer.
We are routinely dazzled by goaltenders’ cat-like reflexes and flexibility, but the movement doesn’t get initiated with a Quiet Eye locating and fixating on the puck.
Eye for an eye
One of the nice things about the Quiet Eye theory is that it has been tested on performers who are actually performing. This wasn’t borne in a lab and tested via simulations or recreations that strain credibility, it’s been fleshed out on the ice and turf with real players wearing real equipment and battling conditions and fatigue and other realistic elements. And this is a tremendous testament to Vickers and her quest for authenticity in the pursuit of fundamental answers.
There are also those who bristle at the notion of any one “optimal” way of perceiving that’s supposed to be applied to an entire population, and I get that.
So it’s necessary to point out some that Quiet Eye has some limitations. A 2022 study by Ben Franks, et al., illustrated one, by looking at the Quiet Eye of professional soccer goalies—with a wrinkle. The researchers set up a penalty kick between one shooter and one goaltender, but they granted the shooter the freedom to dribble the ball liberally, as if taking a real in-game penalty kick.
Their findings showed that the goalies actually expressed a lot of variability in how and when each keeper manifested his Quiet Eye. There was no correlation between the duration of the Quiet Eye and the outcome of the save. And some of the goalies routinely fixated on the ball, while others fixated on the shin area of the kicking leg. (A tentative link was found between the goalies with quicker reaction times and their gaze being on the ball - perhaps because a faster goalkeeper knows he can wait longer for more information and still be able to recover).
Quiet Eye is a “useful tool,” Franks wrote, “in which to investigate how skilled performers regulate action through fixating on visual information within the immediate environment before the onset of a goal directed movement.” Beyond that, however, the sweeping generalizations about how athletes are to use Quiet Eye don’t allow for enough breathing room for individual variation.
This is true probably more so for dynamic actions like goaltending or baseball hitting in which performers have developed a host of subtle or idiosyncratic tricks and cues to prepare them for their task. There are a lot of ways to save a shot.
But an “optimal” duration of Quiet Eye probably can be more convincingly pinned down in more static actions, like golf putting or free-throw shooting. Here are at least two findings that support it:
Evidence from quiet eye training
The next time you do find yourself standing over a putt, here’s a tip based on a Quiet Eye study from Sam Vine, Lee Moore, and Mark Wilson in 2011:
1. Assume your stance and align the club so that your gaze is on the back of the ball.
2. After setting up over the ball, fix your gaze on the hole. Fixations toward the hole should be made no more than 3 times.
3. The final fixation should be a Quiet Eye on the back of the ball. The onset of the Quiet Eye should occur before the stroke begins and last for 2 to 3 seconds.
4. No gaze should be directed to the clubhead during the backswing or foreswing.
5. The Quiet Eye should remain on the green for 200 to 300 ms after the club contacts the ball.
After following this protocol in the laboratory, expert putters not only performed better putting in the lab. They took the lessons from this training and saw improvements on the course, improving the amount of holed putts within 10 feet by 5 percent over the course of the next 11 rounds!
“The findings suggest that QE training may provide a useful psychological technique,” the researchers wrote, “as part of a pre-performance routine, to aid performance under pressure and improve performance in competitive environments.”
There are many other examples like this. One of the most convincing recently was work by Daniel Laby, a sports vision researcher in New York, who used eye-tracking goggles with NBA players for free-throw shooting. The heat maps below show where their gaze was focused, and you can see the differences for yourself:
Exponential Athlete podcast
In other news, I was asked to be on Ken Jee’s excellent Exponential Athlete podcast recently. It was great! I highly recommend following him, and I hope you’ll give our conversation a watch/listen:
Links
Neuroscience is becoming a gamechanger in football … Pupillometry as a new window to player fatigue? A glimpse inside the eyes of a Euro Cup Women’s Basketball team … Why triathletes can’t sleep … Brain scans of jazz musicians reveal how to reach a ‘flow’ state … 1 in 5 young athletes meet criteria for pre-hypertension … Female athletes perform better on their period … Olympian embraces brain training in preparation for Winter Games … Urban athlete superpowers … How climate change is changing sports
References
Franks, Benjamin, et al. "A descriptive case study of skilled football goalkeepers during 1 v 1 dyads: a case for adaptive variability in the quiet eye." Frontiers in Psychology 13 (2022): 908123.
Laby, Daniel. "Visual fixation in NBA free-throws and the relationship to on-court performance." Journal of Sports and Performance Vision 2.1 (2020): e1-e7
Panchuk, Derek, and Joan N. Vickers. "Gaze behaviors of goaltenders under spatial–temporal constraints." Human movement science 25.6 (2006): 733-752.
Panchuk, Derek, Joan N. Vickers, and Will G. Hopkins. "Quiet eye predicts goaltender success in deflected ice hockey shots." European journal of sport science 17.1 (2017): 93-99.
Vine, Samuel J., Lee J. Moore, and Mark R. Wilson. "Quiet eye training facilitates competitive putting performance in elite golfers." Frontiers in psychology 2 (2011): 8.
I see!
Bravo on another fascinating topic.