From cnn.com:
" Tanya Streeter's remarkable lungs and willpower have helped her break world records in free diving, a sport in which competitors dive deep beneath the water's surface on one breath. In 2002, she completed a dive of 525 feet -- a length equivalent to a 50-story building -- on a single breath of air, setting a new record.
Streeter, a native of the Cayman Islands, also has amazed the world with her breath-holding talents. Her time of six minutes and 16 seconds is just five seconds short of the women's record.
Studying how Streeter can function so well without oxygen, University of Texas professor Ed Coyle learned that she has a lung volume almost twice what women her size usually have.
Coyle also focused on the oxygen levels in Streeter's blood when she's holding her breath. Streeter is regularly able to push below 50 percent. By comparison, in an operating room, surgeons consider blood oxygen saturation of less than 70 percent the point at which the brain and heart can be damaged by lack of oxygen.
Streeter said she hopes her abilities can offer researchers insights into conditions such as asthma, sleep apnea or sudden infant death syndrome, and pass on a lesson to others about redefining their own limits.
"You have to accept that somewhere in you, you have a personal limit, but chances are, it's nowhere [near] where you think it is," Streeter said. "Chances are it's going to be much farther, deeper, longer than you thought."
" Ed Viesturs has been called the No. 1 adventure athlete in the world and the "Chevy truck of mountaineering."
He has climbed Mount Everest five times, and, without the use of supplemental oxygen, has reached 13 of the 14 world's highest peaks, all towering more than 26,000 feet high. This spring, he attempts to top Annapurna in the Himalayas, the last of his 14 peaks.


"I like things that are difficult, physically and mentally," Viesturs said. "Things that are really challenging, things that really maybe take a long time but really push me to my limits."
At least 1,200 people have climbed Mt. Everest, most with bottled oxygen to help them breathe. Because of the thin air, climbers take in about one-third the oxygen they would get at sea level.
Viesturs said his body is able to adapt to high altitudes more efficiently than most. Also, doctors said Viesturs has a 7-liter lung capacity, compared with the 5-liter capacity of an average person of his height.
There is a point in climbing where there's not enough oxygen to sustain life, the so-called "death zone." But Viesturs said he believes that even that zone can be surpassed.
"Because Everest is 29,000 feet and we've gone that far, if there's a peak that's 29,500 feet, I'm sure humans could climb it," he said. "I don't think we've reached our limits."
Kamler, the doctor-explorer, agreed, saying he is awed at the human body's capabilities.
"I'm willing to consider almost anything as possible now with the human body," Kamler said. "And the more I study the human body the more amazed I become by what it's capable of doing."

And from BBC:

"Kyla Smith, from Sunderland, was driving her MG ZR hatchback near Washington when it left the road and hit a tree.
Passenger Jonathon Connor's leg was stuck under the car as it rolled over.
So the 23-year-old lifted the car to allow him to escape, unaware that she had injured her back in the crash.
Ms Smith said: "I lost control of car, it hit a pile of bricks, which hit the steering arm and made wheels head for a tree. We hit the tree and the car came down on the passenger side.


"At this point Jonathon's leg was outside the car and it came down on his leg.
"I climbed out of the drivers window and saw that his leg was under the car, so I grabbed the sun roof visor, and lifted the car six or seven inches to get it out.
"I just knew I had to get him free and there was no-one else around at the time."
The 5ft 7in, eight-and-a-half-stone strongwoman was unaware that she was hurt herself.
"I bashed my head on the steering wheel on impact on the tree and as far I was aware I had a black eye and that was it."
She was taken to Sunderland General Hospital, where it was discovered she had damaged a vertebra in the accident.
Joan Harvey, a chartered psychologist at the University of Newcastle said: "What happens in an emergency is that all your physiology gets into gear and you can do things that are really quite superhuman.
"But in this sort of case probably only around 20 to 30% of us would have the wit to do what she did.
"Quite a lot of the rest would stand there and not know what to do, and in fact one or two at the opposite end of the scale might even become a liability and start screaming in panic."

So are these people normal humans or are they metahumans? And where is the line between the two? Sometimes it's a very grey area; hard to tell where one leaves off and the other begins. It's worth noting, though, that these people are all willing to stretch the SUPPOSED boundaries of what a person can do. And that's the point. There IS NO hard-and-fast rule of what you or I can do. Every person you meet has hidden potential, and some of them might be able to do things no one has imagined possible.

Latent metas might be all over the place, just waiting for life to manifest their talents. But you can never find out the limits of what you can do by accepting what other people tell you are your limits.

Don't live half your life. Push the edge of what you know. You may find more to yourself than you thought.

Links to the original articles:

http://edition.cnn.com/2004/HEALTH/05/03/lbl.overview/
http://news.bbc.co.uk/1/hi/england/wear/4746665.stm