CHANDLER, Ariz. » Holding a fiberglass pole, Aria Ottmueller bent and touched the runway to locate her starting mark. A coach helped position her front foot. The foam vaulting pit at her high school appeared only as a blue smudge. The crossbar was invisible to her.

A thousand miles away, in East Texas, Charlotte Brown struggled to distinguish the runway from surrounding grass or artificial turf. So her coach placed a strip of carpet along the edge of the runway to provide a hazy visual contrast and guide her straight toward the bar.

This weekend, Ottmueller, 17, and Brown, 15, are competing in their state track and field meets in the pole vault, pioneers with severe visual impairment who are further redefining what is considered an able-bodied athlete and what is considered a disabled one. In the past, athletes with disabilities were not accommodated in mainstream high school sports. Now, athletes like Ottmueller and Brown are not only competing, but also succeeding against their able-bodied peers.

Brown, a sophomore with a sprinter’s speed, has cleared 11 feet 6 inches, which ranks just outside the top 100 performances this season by a prep vaulter. She will be among the favorites Saturday in Class 3A at the Texas state meet, where she hopes to vault 12 feet or higher.

Ottmueller, a junior, began vaulting only five weeks ago after trying for more than a year to persuade her coach to let her participate. She has cleared 7 feet and hopes to surpass 7-6 or 8 feet Friday at the Division IV state meet in Arizona.

It is not uncommon for athletes with limited sight to participate in running events, or throwing events like the shot put and discus. Marla Runyan, an American who is legally blind, reached the final of the 1,500 meters at the 2000 Sydney Olympics. Later she competed as an elite runner in the New York City Marathon.

But it is extremely rare for the visually impaired to compete in the pole vault. It is one of track and field’s riskiest and most technically demanding events, requiring competitors to sprint down a runway, plant the pole in a box, invert their bodies and turn 180 degrees while flying over a crossbar. Many high schools have eliminated the event because of liability concerns.

The pole vault is not contested in the Paralympics. And until this week, the executive director of the U.S. Association of Blind Athletes said he knew of no vaulters with exceptionally restricted vision.

"In my 20 years with the USABA, I’ve not come across any," said Mark Lucas, who has been executive director of the governing body since 2000. "Pole vaulting is an absolute rarity because of the hand-eye coordination needed. What an incredible accomplishment with low vision."

Ottmueller was born with underdeveloped optic nerves and can see at 20 feet what people with normal vision can see at 400 feet — a condition that will not improve, her optometrist said. She has little or no peripheral vision or depth perception. In school, Ottmueller uses magnifying devices and Braille to read. At the Arizona state meet, given the unfamiliar surroundings, she planned to use a cane to navigate the crowded vaulting area.

Brown developed cataracts as an infant and had surgery. Her vision deteriorated further at age 11 for reasons that remain unclear, her mother said. In her left eye, Brown perceives only light and darkness. And while vision in her right eye can be corrected to 20-400 with a contact lens or prescription goggles, her field of vision is so narrow that "it’s like looking through a straw," said Dan Chamness, who is Brown’s counselor with the Texas Department of Assistive and Rehabilitative Services.

Essentially unable to read large type, Brown now relies primarily on Braille, the form in which her name appears on her letter jacket. She said she could not perceive colors, only blurry shades of black and white. During cross-country season, her teammates wear bells on their shoes to escort her along. This month, on her 16th birthday, Brown is scheduled to receive a guide dog.

She and Ottmueller — one is 5-foot-7, the other is 5-4 — do not know each other but share the drive of honor students, the fearlessness of competitors and a daredevil longing. Unable to rely on sight for vaulting, they have developed a mathematical compensation, counting their strides toward liftoff and trusting that the repetition of training will carry them safely over the bar.

"You can’t be afraid of what you can’t see," Ottmueller said.

In the air they experience a sense of freedom, both vaulters said, a temporary release from the attachment of gravity and the confines of public doubt.

"For a few seconds, nothing is wrong in the world, and nothing else matters," Brown said.

The accomplishments of Ottmueller and Brown will "break down negative stereotypes," Lucas, of the blind athletes association, said. "Seventy percent of kids who are blind and visually impaired are left on the sideline in PE classes. Coaches don’t know how to make accommodations."

As a young girl, Ottmueller began participating in gymnastics and equestrian jumping, enhancing her spatial awareness. She still rides horses regularly. Her mother, Maria Giordano, who is a nurse, said she frequently told her: "Your disability doesn’t define you. Don’t use it as a barrier. You don’t know what you can achieve unless you try it."

Still, Ottmueller was bullied in public school and transferred to private school in the eighth grade, her mother said. Her first choice of a private high school was rejected by officials who thought Ottmueller would be a distraction to other students, Giordano said.

Even at Valley Christian High School, which Ottmueller now attends in suburban Phoenix, Giordano said her daughter was cut from the cheerleading squad, apparently over liability concerns surrounding the potential for injuries during tumbling maneuvers.

Unyielding, Ottmueller broached the idea of pole vaulting last year, telling the school’s track coach, "If I can jump a 1,200-pound horse over a bar, why can’t I jump myself over a bar?"

Dan Kuiper, a highly regarded coach who has won 25 state track championships, was not immediately swayed.

"I kept telling her no; from a liability standpoint it was dangerous," Kuiper said. "I said, ‘I don’t think you understand; you’ve got to be able to see the bar.’ But she was persistent."

Recently, Ottmueller began to wonder, "Is there anyone else out there like me?"

There was. Brown, of Rains High School in Emory, Texas, has been vaulting for four years, since the seventh grade, drawn to it because "it looked dangerous."

Her mother, Stori Brown, a science teacher at the high school, said that Charlotte was inspired by two older brothers who were athletes and that she faced no resistance from school officials about her own aspirations.

"I don’t think Charlotte has ever been told no," Stori Brown said. "We always told her, ‘Yes you can do it, but how are you going to do it?"’

She got permission to use carpeting to guide her on the runway. Her coach is allowed to call out her strides as she approaches the bar. And as Brown has gone higher, she has begun climbing ropes and using gymnastics rings to grow more comfortable in an inverted position.

"We take it for granted when we stick our feet toward the sky," said Derek Smith, Brown’s coach. "She doesn’t know what sky is."

Whatever the outcome at the Texas state meet, Brown said she eagerly awaited a chance to begin working with a guide dog later this month.

"I was thinking he would run next to me and hop on my back and be a jet pack and shoot me up there," she said with a laugh.