By the time Olympic athletes arrive in Pyeongchang, South Korea, they have trained their bodies to near-perfection. But it's how well they've trained their minds that may determine who's more likely to take home a medal.
Many scientists who study athletic achievement adhere to the belief that sports are just 10% physical. The other 90% is mental.
"The physical aspect of the sport can only take you so far," gymnast and seven-time Olympic medalist Shannon Miller told The Dana Foundation in 2012. "In the Olympic games, everyone is talented. Everyone trains hard. Everyone does the work. What separates the gold medalists from the silver medalists is simply the mental game."
They concluded that while some athletes are born with an innate tendency to win, others become better competitors by training their brains over time.
One of the most important things that separates the best from the rest is the sheer speed at which some athletes are able to make decisions.
"The brain is constantly bombarded with sensory information from multiple channels," said Christopher Fetsch, an assistant professor of neuroscience at Johns Hopkins. This includes vision and hearing as well as sensors in the inner ear that relay information to your brain about your body's orientation and movement in space (more on this below).
Fetsch said Olympic athletes "are making split-second decisions on the order of one-10th of a second or less -- doing something that would probably take us more like half a second or up to a second to decide and act."
For example, in downhill skiing, a racer always plans his or her line but must be able to make instantaneous adjustments on the course.
"Perhaps you see a rut in the snow just ahead of you, and you have to make a quick correction that basically cancels out that expectation that you had of where to turn," Fetsch said. "The brain reaches an initial decision and then can kind of revise and cancel that out while the information is still flowing through the pipeline and hasn't quite reached the muscles yet."
But just because these athletes excel at their sport, it doesn't mean they will excel at everything, Fetsch said. "When the brain learns and is trained to a high level on a particular task, in general those skills don't transfer very well to other tasks" such as a different sport or even an office job.
Ever wonder how figure skaters are able to maintain their balance as they perform spins and flips that would make most people dizzy?
Over time, as they train, skaters develop two primary methods for dealing with dizziness, said Kathleen Cullen, a professor of biomedical engineering at Johns Hopkins.
"One approach is something that a lot of people are familiar with, called spotting," Cullen said. "When they're done with their spinning, they actually fixate on a target in the arena, and they can anchor themselves to that and help themselves keep track of how they're moving in the world."
The other technique involves what Cullen refers to as the sixth sense: the vestibular system. It's a complex network of sensors in the inner ear that inform the brain how the head is rotating in time and space, as well as in what direction and how fast it is moving. Cullen said the vestibular system functions faster and is more reliable than vision.
"Once you stop spinning -- because you have these sensors that have fluid in them -- the fluid actually keeps moving because of its own inertia, and that gives a false sense of motion," Cullen said. "And this false sense of motion is something that people who practice spins all the time -- their brain actually undergoes this profound change where it learns over time to suppress that false input."
What's more, Cullen said, the brain builds complex internal models to predict "the sensory inflow that should occur when an athlete performs a particular type of routine."
The athlete can then adjust on the fly "in order to account for the mismatch between the sensory inflow they're experiencing and the sensory inflow they expected."
It's why -- and how -- the top finishers are always able to land on their feet.
Every athlete in Pyeongchang wants to bring home the gold. As if that weren't incentive enough, consider the pride, satisfaction and potential endorsement deals that come along with it.
Vikram Chib, an assistant professor of biomedical engineering at Johns Hopkins, studies how incentives motivate performance. Specifically, his research is focused on a section of the brain called the ventral striatum, an integral part of our reward system.
"What we found is that when people are getting ready to do the task that's on the line, they tend to encode the positive aspects of the rewards associated with winning," Chib said. "But when they're in the act of doing the task itself, they tend to become worried about the loss of those incentives."
In the context of the Olympic Winter Games, this could mean a hockey player is confident he or she will make shot up until the moment they shoot, at which point they may become rattled and choke under pressure.
Chib's advice is to create a level playing field -- in your head.
"Those people who have more flat (neural) activity, that aren't as responsive to incentives -- so they don't go very high for potential gains and very low for potential losses but instead kind of keep constant brain activity, regardless of the incentive -- those tend to be the ones that do better."
That is to say, if you can think about the potential loss ahead of time, you'll be better prepared -- and more likely -- to stay cool, calm and collected.
"They can disregard the fact that the stakes are high," Chib said, "and still come through with the performance that they've practiced all their life to achieve."
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