Nine-year-old Ashima Shiraishi has a career that a climber three times her age would be proud of. The four-and-a-half-foot-tall New Yorker has sent problems as hard as V11 (until last year, no woman had ever climbed harder than V12). She has a sponsorship with shoe maker Evolv, and she'll be starring in her own short in this year's 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.