On a warm, clear, breezy day in the highlands of central Colombia, Luis Cardenas' boys are moving fast, breathing hard, legs pumping, eyes focused on the asphalt ahead, 8,000 feet above sea level.
Cardenas is the coach of a cycling club for teenagers. And he pushes them hard.
"Go, go, go Johan, 500 more meters," Cardenas says.
He's talking to Johan Cardenas, one of the best teenage cyclists in this swath of emerald green mountains and potato farms.
This is a sparsely populated state called Boyaca, and it's a cycling mecca.
In the rural mountains of central Colombia, life is a struggle, and career choices for young men include potato farming and herding goats.
And so teenage boys dream of a different future: cycling to glory in the French Alps and the Pyrenees. That's because the rawboned cyclists from a string of hardscrabble Colombian towns have excelled as climbers in the world's great bicycle races.
Learning To Suffer
Now, hopes rest with cyclists such as the 16-year-old Johan, who is not related to his coach. He has wavy black hair. He's soft-spoken, mild-mannered.
But he also has the taut legs of a cyclist who can climb mile upon mile, up steep and forbidding mountain passes.
And he has something else they say all great cyclists must have: the ability to suffer — a lot.
"If you can't suffer," Johan says, "what good are you?"
In the European racing circuit, Colombian cyclists are famous for withstanding pain.
Luis "Lucho" Herrera is a national hero for winning a mountain stage of the 1985 Tour de France, plowing ahead even as his face was covered in blood from a crash.
More recently, mountain kings have included Santiago Botero, who said he rides like a madman, a warrior.
Then there's Victor Hugo Pena, the mountain enforcer on Lance Armstrong's squad.
Family Support Is Critical
In Boyaca, though, it's not just the racers who sacrifice.
Johan's mother, Marifely Leguisamon, makes ends meet with a restaurant run out of the family kitchen. His father, Yefferson Cardenas, works construction jobs, when he can get them.
To buy a new $6,000 racing bike for Johan, the family even sold its home.
"This is expensive, and sometimes there's no money," Leguisamon says. "And he needs food. He needs rest. He needs a lot of things."
She says their great hope is for Johan to become a professional racer — and to excel.
At a recent bike competition, children barely big enough to walk had their own race. But the highlight for the day was the contest for the big kids — including Coach Cardenas' boys.
As the cyclists passed the finish line, the top three spots went to three racers from Cardenas' club.
Johan didn't win — but he pedaled hard, finishing second.
It was another day on his bike, another good day, another day closer to becoming a professional racer.