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With two team golds already to his name, the 26-year-old South Korean archer, who is legally blind, refuses to wear corrective glasses or contacts or have surgery. With the target lines blurred, he relies on muscle memory. ''Archery requires very sensitive muscles,'' he's said. ''I used to play football at school, and I enjoyed really physical sports, but I now try to avoid any sports that might build up different muscles. That might have a negative impact on my archery.''
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Track & Field, Men's 400m and Men's 4x400m Relay
The first double-amputee to compete in an able-bodied Olympics, South African sprinter Pistorius is known as the ''Blade Runner'' for his carbon-fiber prostheses. Born without fibulas, Pistorius will also defend his gold medals in the 100m, 200m, and 400m at the Paralympics in London.
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Nur Suryani Mohd Taibi
Shooting, Women's 10m air rifle
The 29-year-old Malaysian shooter (left) won't be the first pregnant woman to compete in an Olympics when she takes aim on July 28, but at eight months, she's likely the most pregnant. ''I will talk to her, say, 'Mum is going to shoot just for a while. Can you just be calm?''' she told The New York Times of her strategy. And when her daughter is older, what will she tell her then? ''You are very lucky, you're not born yet and you already went to the Olympics.''
Another great story in the 10m air rifle event: Bahiya al-Hamad, the 19-year-old shooter who is not only among the first female athletes Qatar is sending to an Olympics this year, she's also set to be the nation's flagbearer at the Opening Ceremony. Saudi Arabia and Brunei Darussalam are also expected to send female athletes for the first time. Per the IOC announcement, ''Fifteen years ago at the 1996 Atlanta Olympic Games, 26 [National Olympic Committees] had yet to include female athletes in their delegations. Four years ago in Beijing, the figure had dropped to just three — the three NOCs that have confirmed they will be sending female athletes to London 2012, thus marking a historic milestone in Olympic history.''
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Track & Field, Women's 800m
After impressive victories in 2009, the South African's gender came into question, and she was asked to undergo controversial tests. Though she told South African magazine You she didn't let the controversy get to her —''I see it all as a joke, it doesn't upset me.... God made me the way I am and I accept myself. I am who I am and I'm proud of myself'' — she underwent a makeover for the cover shoot. After 11 months, she was cleared to resume competing. In 2011, the International Association of Athletics Federations, which oversees track and field, introduced new regulations governing the eligibility of females with Hyperandrogenism, or the excessive production of testosterone. The IAAF believes monitoring hormone levels keeps the playing field level, while others consider it a means to police femininity. Either way, 21-year-old Semenya is considered South Africa's best chance for bringing home gold, and that earned her the honor of being the country's flagbearer at the July 27 Opening Ceremony.
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Judo, Women's Half Heavyweight (78kg/172 lbs)
She started judo when she was six, because her mother wanted her to learn self-defense and self-respect. Ten years later, she revealed that her coach had sexually abused her. ''For a long time, I hated judo, and I hated everything associated with it. And what was once my passion kind of became my prison,'' Harrison, now 22, told the AP before heading to London, where she could become the first U.S. athlete to win gold in the sport on August 2. ''But training at this level and devoting my life to something, like this, I cannot help but love it — again.''
Another survivor to watch: 28-year-old Queen Underwood, one of the three women representing the U.S. as women's boxing makes its debut as an Olympic sport. She was sexually abused by her father. Read her triumphant story here.
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Track & Field, Men's 5,000m
Team USA's 2008 flag bearer is one of ''The Lost Boys of Sudan,'' and spent 10 years in a Kenyan refugee camp before arriving in the States at age 16. Earlier this month, he published his autobiography Running for My Life.
A man with a similar story: 28-year-old marathoner Guor Marial. He will run under the independent Olympic flag, but in his heart, he's representing South Sudan, which does not yet have a recognized National Olympic Committee. Having escaped a Sudanese child labor camp when he was eight, he hid in a cave, then made his way to Egypt before landing in America. ''I used to hate running. I was running back home to save my life,'' Marial told the AP recently. But then he ran at a New Hampshire high school and Iowa State. He now trains in Arizona. His marathon time could land him a Top 10 or 20 finish in London, an IOC spokesman has said.
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There's no question this kid, who cried after making the Olympic team, is all heart. Though he now trains at the Olympic Training Center in Colorado Springs, 19-year-old Orozco grew up in a dangerous section of the Bronx, where he was frequently ridiculed for his choice of sport. He got serious about gymnastics, he says, because he wants to give his parents, who've always supported his dream, a better life. He's the kind of son who, at 14, heard his parents, who both have health problems, talking about their bills and asked to work at the gym where he was then training so he could help out. He presented his first paycheck to his father and told him to put it toward the mortgage. His determination earned him the starring role in the Gym Class Heroes' video for ''The Fighter.''
Another family story from the U.S. men's team: Danell Leyva, whose mother fled Cuba with him and his older sister when he was just a toddler to get him better medicine for his asthma.
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Track & Field, Men's Marathon
The Ethiopian refugee now runs for Norway, where he works full-time as an office and school janitor — training during his shift breaks, only traveling to meets that allow him to be back at work on Monday morning — and spends the winter ''running up and down a mile-long service tunnel built for sewage pipes, waiting for the snow to melt,'' according to The Daily Mail. While he's not expected to medal, he's someone for whom you'll definitely find yourself rooting.
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The 37-year-old mother, who won gold with the Unified Team in 1992, returns for her sixth Olympics. As she did in 2008, when she earned an individual silver on vault, she'll represent Germany. She's expected to repeat. Another inspiration in the young, often cruel world of female gymnastics: Romania's Catalina Ponor, who eight years after winning three gold medals in Athens (team, balance and floor), returns to the Olympics at the age of 24.
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Equestrian, Individual Dressage
The 71-year-old Japanese equestrian, who made his Olympic debut at the 1964 Games in Tokyo, will be the oldest Olympian in London and the second-oldest Olympian ever. Swedish shooter Oscar Swahn was 72 when he medalled in 1920.
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Diving, Men's 3m Springboard
Born with 60 percent hearing loss, 27-year-old Colwill, who punched his ticket to his second Olympics by winning the 3m Springboard title in nail-biter fashion at the U.S. trials, can't wear a hearing aid when he dives to hear the sound signaling him to go. Referees will give him a physical cue. Colwill's coach, Dan Laak, has said his other senses are heightened: ''His sense of awareness of where he is in the air and his peripheral vision is exceptional, too. It's almost cat-like the way Chris can see and react to things.''
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Badminton, Men's Singles
Known as ''Super Dan,'' the reigning Olympic gold medalist from China is the only person to ever win all nine major titles in the world of badminton. More interestingly, he's been known to have John McEnroe-esque outbursts and celebrated his Beijing gold by throwing his racket and sneakers into the stands.
Another interesting badminton story — who knew?! — is Tony Gunawan, who won the men's doubles gold for his native Indonesia in 2000 but returns to the Olympics in London under the U.S. flag.
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Diving, Men's 10m Platform and Men's Synchronized 10m Platform
The 18-year-old Brit, who is a medal favorite in his second Olympics, is famous enough in his home country to have released an autobiography, My Story, earlier this year. While he's had to deal with the death of his supportive father, who lost a long battle with brain cancer in 2011 (Tom keeps his ashes in his bedroom and says hello to him every morning), he's also endured critics questioning his focus after he became a media darling. (They care who a diver dates!). Without a doubt, the pressure will be on on his home turf. Until then, watch him lip-synch LMFAO's ''Sexy and I Know It'' with fellow divers.
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Swimming, Men's 50m Freestyle
After winning two medals in Sydney (a gold in the 50m free and silver in the 4x100 free relay), Ervin retired at the age of 22. According to his website, ''Ervin then spent several years traveling the world and exploring other interests, including his higher education, music, tattoos, teaching people all over the world about swimming, and tsunami flood relief.'' (He famously auctioned off his gold medal on eBay and donated the money to tsunami relief in Southeast Asia.) Twelve years after his first Olympic Games, Ervin is back — two tattoo sleeves richer.
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Men's Beach Volleyball
Together with partner Todd Rogers (a.k.a. ''The Professor''), the 6'9'' Dalhausser (a.k.a. ''The Thin Beast'') hopes to repeat his team's gold-medal winning performance from Beijing — minus the opening match upset loss to Latvia. After the 2010 season, the best of their career, Dalhausser was diagnosed with depression. ''I was like, 'How is that possible?' I just had the best year of my life. I was engaged to a great girl,'' he told Time. ''Before I was diagnosed with depression, I never really bought into it,'' he said. ''After dealing with it, I realized, man, this is the real deal. This kind of sucks.''
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Shooting, Women's Skeet and Women's Trap
A lot of eyes will be on Rhode's fellow American shooter, Matthew Emmons, who, while winning medals in men's 10m air rifle in each of the last two Olympics also choked memorably in both Games' 50m rifle three position events. But let's put the focus on 33-year-old Rhode. If she medals, she'll become the first American athlete in any sport to win an individual medal in five straight Olympic Games. According to her official bio, after returning from Beijing, the shotgun she used in her first four Olympics was stolen from her car. She got the gun back in early 2009 when police stumbled upon it in a routine parole check.
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Weightlifting, Women's +75kg/+165 lbs
The 22-year-old sister of New York Jets center Nick Mangold played football from the time she was eight, but she got into weightlifting when she was 18. She had her sights set on Rio 2016 but made the Olympic team now. Fans of MTV's docuseries True Life will recognize her from last year's True Life: I'm a Big Girl. She works a catering job during the day and sleeps on a twin bed in her friend/agent's laundry room at night.
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Track & Field, 110m hurdles
You might recall the painful scene in Beijing in 2008, when the 2004 Olympic champ had to bow out of his preliminary heat with an Achilles injury before his stunned home crowd. Watch it again.
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Track & Field, Men's Javelin
The 23-year-old policeman will become the first Kenyan ever to compete in javelin at an Olympics. Yego had no one to mentor him in Kenya, a country known for its middle-distance and distance runners, so he would go to an Internet café and watch YouTube videos of the sport's elite. Though he may not even make the event final in London, ''Mr. YouTube Man,'' as he's been dubbed, has said competing is enough for him.
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Track & Field, Women's Pole Vault
The 31-year-old lost her chance at a medal in Beijing when, she says, organizers transporting poles to the Bird's Nest for the final accidentally sent one of hers back to the Village with another athlete's equipment. Pole vaulters use different poles depending on the height they're clearing. ''Now I'm much more careful with my equipment,'' Murer told The Associated Press. ''When I arrive for a competition, I'll go straight to the organizers and tell them that I don't want anybody handling my poles unless there is someone from my team monitoring.'' As the 2011 world champion, she hopes she can give two-time Olympic gold medalist Yelena Isinbayeva of Russia a run for her money.