Vision Research Gives Clues How Receivers Survive NFL Combine Drills

Dee Milliner
One of the most challenging and entertaining workout drills at this weekend’s NFL Scouting Combine in Indianapolis is the Gauntlet Drill for wide receivers and tight ends.  Whether or not it relates to real NFL success is debated but it does provide a true test of hand-eye coordination and the ability to change focus while on the move.
Obviously, being able to instantly pick up the flight of a thrown football is key for receivers but also is important for defensive backs who need to turn their heads at the last moment to find a pass.  Now, vision researchers at Tübingen University in Germany have shown that humans actually use extremely small eye movements, called microsaccades, to achieve what’s more commonly known as peripheral vision.

In this NFL video, uber-analyst Mike Mayock provides a great overview of the Gauntlet Drill.  Receivers run straight down a yard line while receiving a series of passes from alternating sides.  The key is to change your focus quickly on the fly.
Here's Florida State's Rodney Smith completing the drill at the 2013 Combine.

As a player takes in the field with his vision, it appears to him as a smooth scan of the environment.  In reality, humans make quick, darting glances, called saccades, at different targets.  Its like our eyes see a movie shot at 3 frames a second while our brain perceives a scene at 30 frames per second.
In between these longer saccades are millisecond movements, microsaccades, that are believed to help the brain fill in missing information from the scene and prepare the eyes for an upcoming shift in focus.
"Microsaccades are sort of enigmatic," said Ziad Hafed, the leader of the Physiology of Active Vision Group. “They are movements of the eye which occur at exactly the moment when we are trying to look at something steadily -- i.e., when we are trying to prevent our eyes from moving.”
In the video link below (click to play), from his lab, you can see the microsaccades when the blue focus point changes from blue to red, while the test volunteer tries to keep their eyes fixed on the crosshair.
video

In describing how our vision and brain work together, Hafed used a soccer analogy. "Imagine that you are the coach of a (soccer) team," Hafed said. "You would normally ask your defenders to spread out across the field in order to provide good coverage during match play. However, in preparation for an upcoming corner kick by your opposing team, you would reorganize your defenders, assigning two of them to become temporary goalkeepers and protect the goal. What I found was evidence for a similar strategy in the visual brain before microsaccades.”
Late last year, Hafed’s research group found that microsaccades actually assist with peripheral vision or the perceived ability to look at two different things at once.  He asked test volunteers to focus on a small cursor on a computer screen while he measured their eye movements with a camera pointed at their retinas.  Then, he added another target off to the right or left of the cursor and measured the microsaccades that occurred immediately before the shift of focus, much like the driver’s vision test we take where we are asked if we see a blinking light on our right or left side of our vision field.
By analyzing the timing of the microsaccades with the correct answers of the volunteers, Hafed realized there was a purpose for these tiny eye movements to prep the brain for the next shift of focus.
The study appears in the latest issue of Neuron.
Back to our football catching drill, when the receivers turn their head while running, their first focus may be on the quarterback but then the in-flight ball appears in the periphery and their next saccade is towards the ball.  Athletic eyes that have been well trained by practice and vision drills will outperform those with less agile vision.  While fast 40-yard dash times and soft hands are important to a receiver, their visual system performance should not be overlooked.
Check out the Axon Sports iPad app that players are training with at the Combine this year.