Carlos Gonzalez swung a red boxing glove at his trainer's jaw. As he reared up for another punch, he pivoted on his right leg - a jointed, silver pole attached to a sneaker.

Seven years ago, a shooting left Gonzalez with a wound that forced surgeons to amputate his leg to mid-thigh. He became one of almost 2 million people in the United States who have limb loss because of vascular disease, trauma or cancer.

When he stood on his first prosthetic leg, he just wanted to walk again. But he soon grew frustrated by its limitations and moved to a new generation of prostheses that has placed Gonzalez, 32, among a growing number of amputees worldwide who are running marathons, bicycling and swimming, sometimes faster than competitors with fully intact limbs.

Twenty years ago, the Paralympic Games drew 3,000 disabled athletes to compete in 16 sports. This summer in London, 4,200 athletes will compete in 20 sports, including track and field, rowing, wheelchair rugby and power lifting.

At UCSF this fall, physical therapists plan to hold the first clinic of what they hope will become an annual event intended to help amputees become athletes. The workshop will teach students to sprint, kick a soccer ball, shoot hoops, play flag football and climb rocks on a wall, among other activities.

Model athletes

Organizers hope to compel patients to model themselves after people like Gonzalez, a patient at UCSF's Orthopaedic Institute in Mission Bay. Day in and day out, the Visitacion Valley resident hammers away in boxing gloves and practices jujitsu, a martial art that emphasizes hand-to-hand combat. Gonzalez dreams of becoming a Paralympian, but for now he'll compete in national cage fighting and martial arts competitions.

"If you put your mind to it and train properly and have the right staff and the right people in your corner, it's pretty much 'Just go for it,' " said Gonzalez, who styles his black hair in a faux-hawk and has tattoos on his neck. "I think I can have a good time and motivate people and inspire. The most important thing is to inspire."

On an evening in February 2005, Gonzalez, a phone to his ear, unknowingly walked into a turf war between drug dealers on his way to his mother's house in the city's Sunnydale neighborhood.

One gunshot rang out, then two. The third bullet hit Gonzalez in the stomach. A subsequent infection in his right leg forced doctors to amputate 6 inches above his knee.

"I was pretty eager to accept it early on," he said, "but it was hard."

Technological marvel

After 10 months on crutches, Gonzalez took his first steps on a prosthetic leg provided by his insurance. Generally, the patient's remaining limb transfers kinetic forces to the device. Inside Gonzalez's mechanical knee, a liquid hydraulic system diminished the speed at which he flexed, bent and extended his knee as he walked.

He quickly grew frustrated because his new limb didn't do much more than help him get around. "I walk fast, and the leg was just kind of draggy," he said.

In 2010, Gonzalez acquired his current prosthesis, a marvel of advanced medical technology. The knee contains a computer chip that automatically adjusts to the weight, distance and speed he puts into each step.

The change has given him the energy to rediscover boxing, a childhood passion, and pick up jujitsu. Moving will never feel natural again, but he's falling back into the swing of things.

"You're thinking about where you have to plant your feet so you don't trip," he said.

Gonzalez, who worked in a warehouse before the injury, is now living off disability insurance and training this year for a cage fight and a tournament in grappling, a form of self-defense. First, he must get permission to use his prosthetic leg.

Until now, professional nondisabled and disabled athletes have mostly competed in separate events. But increasingly, those walls are crumbling, said Matthew Garibaldi, director of UCSF's Orthotics and Prosthetics Center. He points to Oscar Pistorius, the double-amputee sprinter from South Africa who is on the cusp of qualifying for this year's Olympics.

"There hasn't ever been crossover just because the events are different, the techniques are different," Garibaldi said. "But now, certainly, the technology has leveled the playing field (and) the training techniques as well."

Over the past 15 years, modern prosthetic components - electronic technologies, plus materials such as advanced plastics and carbon-fiber composites - have put athletics within reach for people who have lost a limb. "It's mimicking natural body mechanics in a far greater degree of accuracy than they ever have been," Garibaldi said.

Running triathlons

When Geoff Turner runs, one leg ends in a shoe. The other ends in a J-shaped, carbon-fiber blade.

In 1990, Turner, then living in Australia, was riding a motorcycle when he collided with a car. His damaged right leg had to be amputated above the knee.

With prosthetics, Turner has run triathlons and marathons in Chicago, Helsinki and San Francisco, which he now calls home. The 47-year-old risk manager is preparing to do the local Escape From Alcatraz relay race this weekend, a triathlon in New York City in July and a marathon there in November.

When he is seriously training, Turner runs and bikes up to 80 miles a week. "There aren't a lot of above-knees amputees who realize they can run. A lot of people think they can't run," he said. "That's just not true."

There's another reason amputees avoid the arena: It can be prohibitively expensive. A running blade like Turner's can cost as much as $10,000, and each prosthetic limb has to be customized for the wearer. Insurance companies generally don't cover limbs specifically for athletics, so athletes often turn to sponsorships from outside organizations.

"For me, there's no way I would be able to keep on top of the knees I destroy," said Turner, who relies on a sponsorship from Össur Prosthetics for his equipment.

Mira El-Katcha, an occupational therapist at California Pacific Medical Center's Davies campus in San Francisco, said she encourages patients to take up athletics to feel independent again.

"Always at the beginning, the adjustment is hard - just losing a limb and accepting the fact of needing a prosthesis and how their life is going to be," she said. Later, "when they're participating in a sport - and it doesn't have to be in a Paralympic manner, just on a team or playing a sport - they feel like they got back to their own life."

For Turner, every step on the pavement brings him closer to reclaiming his identity.

"I'm not an amputee runner," he said. "I'm a runner who happens to be an amputee."

Learn more

Online: Find out more about UCSF's orthopedics clinics at
