At the age of 20, American Rob Summers was an impressive human: dark-haired, 6-foot-1, 86kgs, he could bench-press 142kgs and squat 192. A star in multiple sports, he had been scouted by Major League Baseball since high school. His baseball team at Oregon State had just won the College World Series. He was working every day to get his fastball, cutter, and curve over 144 kph, well on his way to a lucrative career in the Major League.

Then one July night in 2006 he walked to the end of his driveway in Portland, Oregon, to get his gym bag. A car came out of nowhere, jumped the curb, hit him in the leg, threw him up onto the bonnet and in the air, and drove away. He was paralyzed.

Doctors at the hospital told him that damage to his spinal cord meant that he would never walk again, never stand, never feel anything below his chest, and he’d be lucky to regain the use of his hands and arms.

The future for people with that kind of diagnosis—over a million in the U.S.—is bleak. Incontinence, lack of sexual function, and barriers to everything from work to shopping are common, and their constant sitting leads to major health problems, from blood clots and strokes to back pain and diabetes. Most people handed this prognosis would have cried. Summers, however, looked at the doctors and said, “Obviously you don’t know me very well.”

Spine-injury researchers have learned over the past several decades that cats and rats with damaged spinal cords can walk with electrical stimulation of their spinal cords, but nobody had ever tried this on a human. Rob Summers was the first. In November of 2009, a team of doctors and scientists at UCLA, CalTech, and the University of Louisville teamed up to surgically implant a small array of platinum electrodes on the covering of his spinal cord below the injury site. When these electrodes were turned on, from a source similar to the one used to power pacemakers, Summers felt a tingling in his muscles, from his abdomen to his toes. (His case study was recently reported in the medical journal The Lancet.)

When these electrodes are firing, they replicate the stimulation that would have normally come from his brain. It’s a bit like turning up the volume in Summers’ nervous system. This raises the excitability of the nerves below his injury, which allows them to function again. Three days into his post-surgery rehabilitation at the University of Louisville, Rob Summers did something no other paralyzed person on the planet has ever done: Under his own power, he stood. Said one of the researchers, “I was afraid to believe it when I saw it.”

Now 25, Summers has since continued to set records in spinal-cord-injury recovery. He estimates that he has spent more time on a rehabilitation treadmill than anyone but Christopher Reeve (whose foundation paid for much of this research). He now stands unassisted for an hour every day, and has walked on a treadmill for four minutes. Some day, he’ll play baseball again, he intends.

Summers and his doctors are quick to point out that the device in his spine, called epidural stimulation, does not yet constitute an available cure—he’s the first human to try this, and they have many technical problems still to work out. It does, however, suggest a future when spine-injured people can leave their wheelchairs and walk again.

In the meantime, just being able to stand brings major health benefits. Summers has found that the movement made possible by the stimulator has improved his blood pressure, heart-rate, lung, and circulatory functions. He’s regaining muscle. He has recovered some feeling below his injury site, suggesting that the stimulator is actually causing damaged spinal tissue to regrow. He needs fewer medications, he feels less pain, he’s likely to live longer.

And needless to say, he’s a lot happier about everything—even needles. “At the doctor’s office the other day,” he says, “they gave me a shot, and I could actually feel it.”