Loi Ho is doing push-ups and pull-ups and hanging from door frames by her fingertips to prepare her upper body for a rock climbing competition this week.

Her lower body just needs some stretching and one adjustment. When she gets to the climbing gym in Pontiac, Mich., on Friday, she'll take off her artificial leg and wrap athletic tape around the bottom of her right thigh. Then she'll try to defend her first-place finishes in the past two Extremity Games.

Ho, who was born with a congenital deficiency that stopped her right leg from developing below the femur, is one of about 80 participants with an amputation or other limb difference registered in the games that begin Thursday near Detroit. Other events include mountain biking and motocross racing, martial arts, skateboarding, wakeboarding and kayaking.

While other rock climbers missing lower limbs will compete with prosthetic legs, Ho, 29, learned to climb without hers. She had never trained for any sports competition before the first Extremity Games in 2006.

She found that her everyday prosthesis that fits around her right thigh like a vacuum hindered her mobility in a climb.

"Every time I flex in a certain range of motion or bring my leg too far up, I lose suction. There's a gap that air gets in and my leg falls off," said Ho, who just completed her residency as a prosthetist in Naples. She's been testing a specialized prosthesis that can hold up to climbing and wakeboarding, but she wasn't sure it would be ready this week.

Ho is one of about 1.7 million people living with limb loss in the United States, though more than 40 percent of those are age 65 and older, according to statistics compiled by the Amputee Coalition of America.

Amputee athletes have become increasingly ambulatory since the mid-1980s, replacing the wheelchair team sports that became popular with Vietnam veterans, said the coalition's CEO, Paddy Rossbach.

Now track and field, swimming and cycling are giving way to skateboarding, surfing and rock climbing, she said. Younger people have grown up seeing these so-called action or adventure sports televised and become increasingly accessible, and wounded veterans returning from the wars in Afghanistan and Iraq sometimes find them incorporated into their rehabilitation.

Recreational therapist Dave Donaldson has fitted "surf arms" and "surf legs" for wounded veterans in surfing clinics at the Naval Medical Center in San Diego.

Surf arms add a paddle to prosthetic arms, and rubber tips are added to shortened prosthetic legs that give the wearer a more stable surfing stance. The modifications help amputees get onto the surfboards and preserve the physical benefits that come from surfing, Donaldson said.

"You don't want to pile on all the adaptations because it changes the nature of the activity," Donaldson said. "Too many adaptations and it's canoeing or something."

The Extremity Games started three years ago when customers buying artificial feet from Michigan-based College Park Industries asked for prostheses that could withstand more intense activities, said Beth Geno, one of the Games' co-founders and a former College Park employee.

"We had been hearing from so many of our users that they have the Paralympics, they have the events that offer track and field, but not the extreme sports. A lot of people had come more into that lifestyle," said Geno.

Lighter and stronger materials, quick-release connections and components that can be adjusted for different activities have changed the perception of what's difficult for amputees with artificial limbs to do, said Dan Cox, College Park's national sales manager.

Adaptations once only seen at the Paralympics are trickling down to amateurs expecting similar effects in hobbies like skateboarding and mundane activities such as chasing the family dog, Cox said. The company developed a more flexible prosthetic foot to meet such demand.

"Skateboarders were wearing that type of foot, also, because they have to flex when they get down and use different angles," he said.

The adaptations seen in each event depend on the athletes' disabilities. Upper extremity amputees have gear adapters to shift effectively in mountain biking or picks to hoist themselves up a rock climbing wall.

The Amputee Coalition of America is lobbying for insurance companies to provide more coverage for protheses. When specialized protheses aren't available, though, disabled athletes find other ways to adapt to existing equipment, said Daniel Gale, executive director of Adaptive Action Sports.

He points to a teenage skateboarder born without one leg above the knee. Instead of standing on a prosthetic leg, the teen puts all his weight on the deficient limb and pushes himself into tricks with his foot.

"You can't convert the wall or the holds or anything," Ho said. "As an amputee, you just have to find your own way of getting through it."