Coaches like to say if you can do something once, you can do it every time. What makes  Stephen Curry special isn't that he can throw a basketball through a hoop from 30 feet away; it's that he can do it so reliably, under all different circumstances, and always at an angle of precisely 46 degrees

That consistency is the result of thousands of hours of practice, of course. But a new piece of sports training  technology has demonstrated an ability to accelerate that process. The device,  Halo Sport, is a headset that sends electrical current through the wearer's scalp and skull, directly into the brain's motor cortex, where it puts neurons into a state of heightened receptivity. 

When achieved before or during training, this "neuropriming" effect promotes faster acquisition of skills and greater strength gains. These effects have been documented in double-blinded trials carried out with members of the United States ski team, and they've convinced teams in the NBA, NFL, and Major League Baseball to add Halo Sport to their training programs. Next month, the technology will have its debut on the world stage when a handful of track and field stars who incorporate it in their training compete in Rio at the Summer Games. 

"I could never have predicted when we founded this company that we would be working with pro athletes," says Daniel Chao, co-founder of Halo Neuroscience. A trained medical doctor with a master's degree in neuroscience, Chao and his co-founder, Brett Wingeier, previously helped develop the NeuroPace, a sort of pacemaker for epileptic patients. Implanted within the brain, it recognizes the electrical patterns of an incipient seizure and uses pulses of current to "normalize" the activity. 

While the NeuroPace achieved its aim, Chao and Wingeier became curious about whether there were uses for neurostimulation that didn't require brain surgery. They compiled all the research they could find in a gigantic spreadsheet and added some original studies of their own. "Our data was most impressive in the motor system," Chao says. "We said, 'Who needs to move well? Athletes.'" 

Halo Sport looks like a pair of ordinary headphones, but concealed under the band connecting the (functional) earpieces is a row of foam nubs that press through the hair into the scalp. When moistened with saline solution, they conduct electrical current to the neurons of the brain's motor cortex.

The mechanism behind neuropriming is surprisingly simple: Basically, the electrical energy makes it easier for neurons to fire when stimulated by other neurons. More neurons firing means more muscle fibers contracting. And the effects are lasting. "There's this old adage in neuroscience: Neurons that fire together, wire together," Chao says. In effect, the patterns of neuronal firings rehearsed within a neuroprimed state are stronger, and the neurons "remember" them longer. In a trial involving two groups of ski jumpers, the group that used a sham device delivering a non-therapeutic dose of current improved the power and timing of their jumps by 18 percent, but the group that trained after real neuropriming improved by 31 percent. 

That kind of potential is compelling stuff for an athlete like Mikel Thomas, a 28-year-old hurdler from Trinidad and Tobago who will compete in Rio in August. Thomas, who stands 5'8", is several inches shorter than most of his competitors in a sport that rewards a high center of gravity. He makes up the difference by having the power production of a bigger man. "I'm a little bit of a Mighty Mouse," he says. 

But where he really sees the benefit of Halo is in helping him to achieve greater consistency and rhythm in his strides and leaps. "The hurdles is an event where you have ten opportunities to fall on your face," Thomas says. "If you can eliminate the amount of mistakes you produce by replicating what you just did, it would produce a successful race." 

Chao calls this kind of quality control "stereotyping" of movements. It's the key to hitting that long three-pointer, then being able to shoot another one exactly like it. Teams like Curry's Warriors evidently agree. Down the road, Chao sees the technology having medical and rehabilitative applications, but before that happens Halo plans to ship its first consumer units. A pre-order offering earlier this spring sold out in a week. Starting today, the company is again taking pre-orders, with a device costing $649.