Some of those kids grow up and become messengers and then they get real impressive skills LOL. We had 3 or 4 of these guys here working as messengers for a couple of years, they were wicked fast and had unbelievable skills, the kind of moves that are sooooooo silky smooth and deliberate that it just leaves you shaking your head in disbelief. Like bunnyhopping up onto walls with a track bike, bunyhopping curbs on a fixed gear while riding one handed with a cup of coffee in the other. Riding massive gears and being able to stay out of the saddle for 10-20mins at a time, although Ive learned that trick myself..
BMX riding and racing especially is like a crit with jumps and obstacles, some of these kids and young adults can easily put out 300+watts and bursts of around 700+, it aint the bike, its the rider.