Homosassa, Florida (CNN) Kelly Thomas inches across the soft grass, using a walker to navigate her way. Each step is exhilarating and exhausting. She pauses amid the 90-degree Florida heat and smiles.

"It only takes a little bit of try -- and by a little, I mean a lot," she says.

Thomas, 24, is one of three paralyzed patients who can now walk again, thanks to a stimulation device implanted in her lower back coupled with intense physical therapy. News of the patients' progress -- considered an important medical advancement -- was published in separate studies in two scientific journals on Monday.

On a recent sunny day, Thomas returned to the spot that took so much from her on July 19, 2014. It's where the truck she was driving came to a halt after flipping four times around a bend on Halls River Road and smashing into a tree. Her body was motionless, hanging halfway out of the mangled wreckage. She was blue and getting cold.

She has driven past the scene of the crash many times since then to try to jar her memory. To help remember what happened that night. To piece together the moment that changed everything. Nothing seems to work.

The scene of the accident that left Kelly Thomas paralyzed.

Visiting this time, she walks toward the tree, talking to her legs to motivate them to keep moving. "One foot in front of the other," she says. "Slowly but surely."

At 5 feet, 1 inch tall, she is a spitfire of inspiration. Her grit shows immediately, not just from when she walks, but also when she talks.

"Paralysis isn't in my dictionary."

"Don't call me handicapped, because I'm not."

"Thank God, I was raised cowboy tough."

It takes several minutes for her to walk the 40 feet from her car to the tree. Every step is worth it: Today is about triumph rather than a search for lost memories.

"I tell you what," she says. "It does feel good to be standing where I thought my life ended."

She woke in a hospital a couple of weeks after the accident, with tubes and wires seemingly hooked up to everything. At 19, she was paralyzed from the chest down.

Thomas stands next to the red maple where the truck she was driving came to a halt. "The stimulator is facilitating my movement," she says, "but my strength is coming from within."

She told her neurosurgeon she would walk again, no matter how slim the odds. He left the room and told her mother not to "go chasing something that's never going to happen."

The journey has been in no way easy.

There were tears and screaming fits. In moments of desperation, she would say to God, "I don't know why this has happened, but if you can help me to understand this, it might make it a little easier."

She had planned to become a physical therapist to help others. Her mission changed that fateful July day. She's now helping others by taking steps and speaking up.

The trunk of the red maple still bears scars from the crash, with chunks of bark missing from when truck and tree met.

As she stands next to the tree, Thomas searches for the words to describe her emotions. "It's somewhere between 'I told you so' and the impossible," she says. "Somewhere between possible and impossible.

"Being here gives me a sense of power, because I lost a life here. But I also gained a brand new one. And I'm proud of the new life I have."

Transforming the spinal cord injury field

Thomas is part of innovative research conducted at the Kentucky Spinal Cord Injury Research Center at the University of Louisville.

In a study published Monday in the New England Journal of Medicine, two of four patients with "motor complete spinal cord injury" -- meaning no voluntary movement below their injury -- were able to walk again after being implanted with a spinal cord stimulation device and then undergoing extensive physical therapy. They walk with the aid of walkers.

Thomas became paralyzed at the age of 19. Always active in life, she made a pledge to herself that she'd walk again, no matter the odds.

"This should change our thinking about people with paralysis," said Susan Harkema, one of the lead researchers on the project and a professor in the Department of Neurological Surgery at the University of Louisville. "It's phenomenal. This new knowledge is giving us the tools to develop new strategies and tools for recovery in people with chronic spinal injuries."

Claudia Angeli, the other lead researcher and a senior researcher at the Human Locomotion Research Center at Frazier Rehab Institute in Louisville, said it's a fascinating time to be involved in spinal cord research, bringing together decades of investigations culminating in modern-day breakthroughs.

"It just shows the capacity of the spinal cord and how much we're learning about using the epidural stimulation in combination with therapy," Angeli said.

14 paralyzed people who have received what is called an epidural stimulator implanted over a portion of the lower spinal cord, enabling neurons below their injuries to receive signals the brain used to send before their accidents. Over the years , their research has involved14 paralyzed people who have received what is called an epidural stimulator implanted over a portion of the lower spinal cord, enabling neurons below their injuries to receive signals the brain used to send before their accidents.

All 14 patients have experienced voluntarily movement with the implant, the researchers said. They also showed improvement in bowel and bladder function.

The latest study focused on four patients, including Thomas who underwent therapy twice a day for five days a week for many months. A morning therapy session would involve working on stepping; an afternoon session would focus on standing. Thomas's therapy lasted 10 months after receiving the implant.

Thomas says she has to focus on every step to walk. Sometimes, she talks to her feet to keep them moving.

All four were able to stand independently, and two were able to walk over ground, the researchers said. One patient fractured his hip, setting his therapy back by several months, the researchers said.

The other patient who was able to walk over ground had been paralyzed from his neck down with no ability to move his arms until he received the stimulator. "With the stimulator off," Angeli said, "he can't even sit up."

Harkema and Angeli said they believe the positive results were the combination of the stimulation and improved physical therapy treatment.

Harkema underwent a federal investigation a couple years ago. Certain research activities were determined to be in violation of federal regulations, according to a letter from the Department of Health and Human Services in 2016. The letter states the University of Louisville took adequate corrective actions to address the noncompliance. Harkema says she stands by her work.

What's it like to see people who are paralyzed walk again?

"I draw inspiration from every person with a spinal cord injury who comes into this program," Harkema said. "They each have their own unique personalities and spirits. They are just pioneers."

Adding to the excitement of these advancements, another study published Monday in the journal Nature Medicine unveiled similar results. A man paralyzed since 2013 regained his ability to stand and walk with assistance due to spinal cord stimulation and physical therapy, according to research done in collaboration with the Mayo Clinic and the University of California, Los Angeles.

Thomas uses a walker with front wheels. She says her top goal now is ditch the walker one day.

"What this is teaching us is that those networks of neurons below a spinal cord injury still can function after paralysis," Dr. Kendall Lee, the co-principal investigator and director of Mayo Clinic's Neural Engineering Laboratories, said in a press release.

There have been other cases in recent years in which paralyzed people have risen from their wheelchairs and walked. One study in 2015 and another in 2016 showed success in using rehabilitation combined with what is called "brain-computer interface," in which brain signals were sent to an electrical stimulator or exoskeleton resulting in the generation of muscle activity, allowing some patients to walk.

"They're different in terms of the way to activate the central nervous system, but the overall outcome is similar," said Monica Perez, a professor in the Department of Neurological Surgery with the Miami Project to Cure Paralysis at the University of Miami.

Monday's studies, Perez said, provide important additional evidence to the continued advances being made in the spinal cord injury field. She said it shows more proof that people with severe paralysis often have residual connections that "can be engaged in a functionally relevant manner -- and that's amazing."

"What the studies demonstrate is that those connections in the central nervous system can still be recruited, even though you have an injury from years ago," said Perez, who was not connected to either study.

From a scientific point of view, she said, an important consequence of the studies is the awareness "that we need to work harder to understand how we can better involve those connections," she said. "These people with more severe paralysis are regaining this level of function -- and that is beautiful. We also need more accurate assessments of our patients."

"It's not the first time an individual with severe clinically complete paralysis has walked with assistive technology without the help of a therapist," she said. "But it's tremendously important that in more cases the potential of these approaches can be demonstrated."

Harkema and Angeli, whose study was funded in part by the Christopher and Dana Reeve Foundation, said it's imperative for stakeholders to come together to fund more research to help as many of the 1.2 million people with paralysis. More than 8,000 have expressed interest in being research participants in their program.

For Thomas, it's even more personal. She wants others with injuries as severe as hers to experience the transformation she's gone through.

"Nothing's going to be able to stop me in life, because I took something that was thought to be impossible, and I turned it into possible," she says.

'Way too many things to do'

Since she was a child, Thomas has loved to ride horses. She'd saddle up her horse Shadow and take off across the family's ranch. At rodeos, she and Shadow were inseparable.

"All you need is love and a horse," the motto next to her bed says.

In her late teens, she would run 3 to 4 miles a day, train horses and do endurance weight training at the gym almost every day. She worked as a waitress while attending college to become a physical therapist.

All of that was shattered in an instant. The young woman who had been so active was now confined to a chair at the age of 19. It was a fate she could not accept.

Thomas still rides her horse Shadow, but she needs assistance getting on. Her goal is to be able to saddle Shadow herself and hop on with no help.

Not only had she lost her ability to walk, she'd lost bladder control and sexual function. If she went outside, her body temperature would skyrocket over 101 degrees because it could no longer regulate itself. Every bit of her independence, she felt, had been stripped.

"I was lying there saying, 'there is no way I can sit in this chair the rest of my life,' " she says. "I have way too many things to do."

To walk again, she'd have to "cowboy up," as she puts it. She'd rely on the toughness instilled in her by her father from working on the ranch.

It would push her to the limits, at times leaving her on the floor crying, wanting to quit. She'd heard about the program in Louisville. She first went for a screening in January 2017. She returned a month later and stayed through May to do physical therapy, working on standing and stepping for an hour every day.

The stimulator would require a major surgery and a commitment to stay in Louisville for at least a year. She wrestled with the decision. She talked with several men who had the stimulator. They had made gains after the implant, but at the time, no one had walked. She thought, "what's the point of going through so much work?"

"Just being able to stand or wiggle my toes," she says, "was not enough for me."

Thomas's room is decked out with horse mementos from her days at the rodeo.

One of her sisters spoke with her. She told Thomas that she didn't want her to wonder "what if" for the rest of her life. No one knew what Thomas' decision would be.

On August 5, 2017, the family's vehicle was loaded up. "Are we going?" her father asked.

They drove the 13 hours to Louisville. The stimulator was implanted the next month.

Sensation swept through her body as soon as it was turned on."There was this rushing vibration," she says. "It was like a highlighter of my muscles. All of them were contracting. It was wild."

The real work lay in the months ahead. She had endured physical therapy sessions three times a week for three years prior to the implant. That helped set her on a path for success, she says, but it was nothing close to how hard the work over the next year would be. She attended physical therapy fives times a week, a couple of hours every day.

She clung to her faith during the most agonizing sessions, repeating phrases to herself: "I can do all things through Christ, who strengthens me" and "God is with me. I will not fail."

"I tell you what: After the implant, I was introduced to a whole new ballgame," she says. "The hardest thing I've ever had to do in my life. I prayed my way through so many sessions, just to get me through, because I wanted to quit."

Thomas says growing up on her family's ranch made her tough and prepared her for the journey.

The stimulator does not move her legs for her. It stimulates neurons and nerves, allowing her to consciously control the movement.

It began small -- wiggling of toes -- then one leg being able to move and then figuring out how to sync her legs to be able to walk.

She was wearing a black T-shirt with the phrase "No Days Off" on that magical day in February. She took a step or two, and then her therapist broke out in dance. The two hugged and cried. "Oh, my God," Thomas said.

She wiped away the tears and took more steps.

It was like trying to pat your tummy and rub your head at the same time, she says explaining how it felt trying to coordinate her legs, body and mind.

"Trying to trust my body, trying to find a cadence, was very hard."

Finding her calling

Thomas can now walk and talk at the same time, but she still must focus on each step.

She presses a device against her abdomen to turn the stimulator on. "I'm still paralyzed as can be without it," she says.

To turn her stimulator on, Kelly uses a magnet hooked up to this device and presses it against her abdomen.

When she stands, she asks herself, "How do I walk, again?"

Beyond helping her walk, the stimulator has restored sexual function and much of her bladder control. She has regained muscle mass, and nerve pain in her right foot has disappeared. "I'm totally pro stimulator. I love it," she says.

Strolling across her front lawn at the family ranch, she says that her No. 1 goal in the short term is to get rid of her walker. She'd love to be able to run again.

She points to the nearby barn that houses Shadow. She longs to be able to walk to the barn by herself, saddle her up and get on. She'd longs to get Shadow in a full gallop again.

"That's the day I'll accept that I'm healed," she says.

For now, she's taking every day one stride at a time. She says her story is not about herself; it's about helping others. She's buoyed by messages of support from friends and strangers alike. She says it's for them that she works so hard.

In town, that encouragement is on full display.

"I just want to tell you congratulations, sweetie. You're doing beautiful," a woman tells her outside the Homosassa Public Library.

A man in a pickup sees her struggling at her car. "Need some help?" he asks.

"No, sir," she responds. "I've got it."

Thomas stands at the spot where she was left paralyzed in 2014. She said it was empowering to be able to walk and stand at the scene.

She exemplifies a fierce determination like few others. Through her struggle, she's found her calling. Being around her, one can't help but be inspired. She rattles off an array of powerful messages.

"Even if I can't physically help people like I initially intended to do, I can dang sure encourage, help and motivate."

"I carry on with my life like nobody's business, even if my legs aren't working so great."

"The stimulator is facilitating my movement, but my strength is coming from within."

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That strength is what's gotten her this far. Her 19-year-old brother, Sam, sums it up in cowboy speak: "There's nothing she can't do. That's for sure."

He lifts his sister onto Shadow. Kelly and Shadow trot around the front yard. She doesn't know when, but she says one day, she'll hop on without her brother's help.

"I don't have a time frame," she says, "but I have physical goals to get me there."

The moral of her story, she says, is never underestimate a cowboy.