She is 4 ft., 9 in., weighs less than 100 lbs., and when she smiles the braces on her teeth make her look half her 21 years.
But no one should mistake Daiane dos Santos's apparent physical slightness for frailty. When asked what it would mean to win the Olympic gold in floor exercise for which she is heavily favored, the little gymnast does not define what it would mean. She defines what it will mean.
"It will," she says confidently, "be the greatest achievement of my life."
Ms. dos Santos has reason to be confident. Poor, black, and a late adherent to a sport where some girls seemingly swing from parallel bars before they can walk, she has deftly overcome the hurdles put before her - both in sport and life.
She is the current world champion in the floor exercise. She is poised to become the first Brazilian woman ever to win an individual Olympic gold and the first black woman ever to take an individual gymnastics gold. The woman known as the "black pearl" has established herself almost overnight as a hero to millions of Brazilian girls and an example to the country's black minority.
"She is a black woman from a poor background with great talent, professionalism, and an enormous will to win, and many people see themselves mirrored in her," says Brazil's Sports Minister Agnelo Queiroz. "She represents the confidence and ability of Brazilians to overcome difficulties. She is a perfect example of how anyone can reach the top regardless of the color of their skin."
Although she was a Brazilian national champion, she was unknown outside gymnastics circles until last year when she hit the headlines by pulling off two maneuvers never before attempted by a gymnast. The moves - double midair somersaults executed with legs outstretched - brought her gold medals in the World Cup and World Championship and the recognition of the International Gymnastics Federation. It awarded both moves the maximum Super E degree of difficulty - and named one the "dos Santos" (the other is yet to be given a moniker).
Dos Santos is expected to perform both moves in Athens in August, and if she performs them well she is almost guaranteed a gold. The turns are so difficult they take months to perfect and she suspects that none of her competitors will have time to incorporate them into their routines.
"They are the two most difficult tumbling passes that anyone in the world is doing," says Shannon Miller, the most decorated gymnast in US history and a fan of dos Santos ever since she saw her perform at the World Championship last year. "To bring gymnastics to an entirely different level is an incredible feat. Sometimes when you get to a certain level and everybody is doing the same skills, you think maybe it's OK if I just do these skills. But not Daiane, she pushes the limits and goes one step further."
Dos Santos seems to be making a point of going one step further. Off the mat, she has won attention as one of the country's most prominent black sports figures and recognition for denouncing the racism that can affect the 44 percent of Brazilians who are either black or dark skinned.
"As a black, I am proud to be in the team," she told the newspaper Folha de Sao Paulo. "When someone of my race reaches a position like mine, I know how difficult it is. I have never been discriminated against in gymnastics, but I don't agree that there is no racism in Brazil. There is."
That candor has also helped her emerge as a powerful force in promoting gymnastics - a sport that until recently did not enjoy widespread appeal in Brazil's macho culture. Just as Ayrton Senna made Formula 1 compulsory viewing here and Gustavo Kuerten turned millions of Brazilians into tennis fans, dos Santos's success has prompted a jump in interest in the sport, with thousands of people turning out to see the recent World Cup event in Rio and millions more seeing her face plastered across the front of newspapers and magazines.
Her rise to fame has been so meteoric that last month she vaulted over dozens of other more established celebrities to assume top billing alongside soccer legend Pelé when the Olympic torch came to Brazil for the first time; the pair were the first and last Brazilians chosen to hold the flame during its triumphant parade through the streets of Rio.
Such attention has only increased the pressure on her, but dos Santos displays a confidence and balance that belies her tender years. Even the challenge of shouldering Brazil's hopes into Athens doesn't fazeher.
"I know that all eyes will be on me, a Brazilian with a chance for an Olympic medal," she says. "But I try not to think about it. I am only concentrating on training properly so that I will be ready when the time comes and be able to give my best. I have a responsibility inside me, but I have not promised a medal to anyone.
"Winning a medal is every athlete's dream," she continues. "It will validate [my] work."
Note the "will."