Twelve-year-old Ashima Shiraishi has a career that a climber twice her age would be proud of. The diminutive New Yorker has sent problems as hard as V13 (until 2012, no woman had climbed harder). She has a sponsorship with shoe maker Evolv, and in 2011 she had her own short at the Reel Rock Film Tour.



Ashima isn't the only climber to push the sport's limits while too young to drive. Chris Sharma was 14 when he made the first ascent of Necessary Evil (5.14c), then the hardest climb in the United States. Enzo Oddo was 15 when he redpointed his first 5.15, Realization, as was Johanna Ernst when she won the women's lead World Cup in 2008. So how do these kids pull as hard as adults?



Hormones. Audry Morrison, a UK-based nutritionist who has co-authored studies on climbing performance and injuries in children, says that young climbers have a window of opportunity for big performance gains during their growth spurt, which usually hits between the ages of 12 and 16. A surge in testosterone and other sex hormones during this period enables adolescents to pack on muscle at an accelerated rate. As a result, they quickly build the grip strength and speed to pull off harder and harder moves on the rock.



"When you have the adolescent growth spurt, you see some serious climbs happening often," Morrison says.



But while young climbers may progress faster than adults, they're also at a much higher risk for injury. As Morrison points out, the connective tissues—ligaments and tendons—in teenagers going through their growth spurts are two to five times weaker and more likely to tear than those of adults. Overly downsized shoes can also wreak havoc on young climbers' feet by effectively "binding" them, leading to serious deformities.



Even climbing's culture may pose a threat to young athletes' health. A study conducted by American researcher Phillip Watts, a professor of exercise science at Northern Michigan University, found that young competitive climbers tended to be shorter and have lower body fat than other athletes. Morrison sees the report as disturbing evidence that youngsters may be starving themselves for the sport.



"There are restrictive eating practices in climbing for sure," she says. "When a coach says 'you want to get better at climbing, you just have to lose weight,' saying that to a young climber can trigger eating disorders [and] it will really have an impact on their health and their development." While children do tend to have a naturally higher strength-to-weight ratio than adults, kids who push it by undereating can delay maturation or even permanently stunt their growth.



Instead of strength training or limiting calories, young climbers are better off focusing on their technique. Pre-pubescent kids have what Morrison calls "an accelerated ability for movement," and by zeroing in on skills like footwork and body positioning, they can set the stage for big gains later.



For those older climbers disheartened by Ashima's early-blooming generation, there's good news: there's still plenty of time to catch up. Despite the popular perception that sport climbers' lives end in their early thirties (see the hoopla surrounding Sharma's 30th birthday), there's no biological reason that athletes who take care of themselves can't keep climbing hard. Morrison uses the example of Steve McClure, the British climber who at 37 years old established Overshadow (5.15a), the UK's hardest confirmed sport route. While Morrison admits she and other researchers don't know exactly what factors predispose a child like Ashima to bloom early or an adult like McClure to stay fit late into life, one thing's for sure: climbers aren't born with expiration dates stamped on their heads.



"We would always like a young climber to become an old climber," Morrison says. "Climbing should be for life."

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