MANKATO – At the squeal of an air horn, the bik­ers charged out of a start­ing gate, banked a right-hand turn and — legs churn­ing and tires claw­ing at a grav­el path — pedaled up the face of an alp­ine run.

The rau­cous, el­bow-to-el­bow start this past Sun­day at the Mount Kato Ski Area looked like a group of vet­er­an bi­cy­clists, but un­der the hel­mets were kids, at least one of them just 12 years old, tak­ing on a 4-mile lap that sent them climb­ing and de­scend­ing at pun­ish­ing speeds.

"This is my life!" said a wind­ed but smil­ing Jo­sie Welsh, a ninth-grad­er at Robbinsdale-Arm­strong High School in Plymouth, moments af­ter tak­ing se­cond place in her race.

In a state where hills large­ly sub­sti­tute as moun­tains, the club sport has grown with star­tling speed across the state. In its in­au­gu­ral sea­son two years ago, the Minnesota High School Cyc­ling League had 151 rid­ers. Now it's at 550 kids on 41 teams state­wide.

"When we think of the stick and ball sports, there may be 40 kids on the team, but there's a lot of kids who don't get the court time," said Josh Kleve, the league's di­rec­tor and co-found­er. "In our sport ev­er­y­one has an op­por­tu­ni­ty."

The league's growth has been fu­eled in part by its de­ci­sion this year to al­low mid­dle schoolers to race. A surge of sev­enth- and eighth-grad­ers re­spond­ed, tak­ing part in the league's fall sched­ule of five rac­es from Rochester to St. Cloud.

De­spite the growth, the sport still shows sign of its in­fan­cy. When rid­ers wear their team jer­seys to school, "oth­er kids will say, 'I didn't even know we had a team,' " said Ted Siefkes, a mid­dle-school teach­er and coach for the Independent School District 196 team.

Even the rid­ers are still catch­ing up. Anastasia Anto­vich, 13, nabbed two first-place fin­ish­es in her first two rac­es this fall while rac­ing for the 196 team, then in the next race fell to third be­cause she slipped off her ped­als dur­ing a sprint for the fin­ish line. Soon af­ter, she bought a pair of the cleat­ed ped­als that lock to a cyclist's feet and are stan­dard is­sue in moun­tain bike rac­ing.

The push of young rid­ers in­cludes at least one sixth-grad­er, who quali­fies be­cause he's 12 years old. Braeden Anderson, from Brainerd, reg­u­lar­ly posts the fast­est times in the ninth-grade rac­es. He did it a­gain in Mankato, tak­ing first place by 4 sec­onds.

"He's just a tiny guy," said his fa­ther, Shaun Anderson, one of the coach­es of the Cuyuna Lakes High School Mountain Bike Team. "It's fun to watch."

Trails ex­pand­ing

The cyc­ling league's rapid growth has giv­en fresh mo­men­tum to moun­tain bike trail-build­ing pro­jects around the state, with new tracks or ma­jor ex­pan­sions planned or underway in Duluth, at Theo­dore Wirth Park, Lake Re­becca Park Reserve and at the Cuyuna Mountain Bike Trail System, the state's moun­tain biking gem near Brainerd. The Cuyuna mas­ter plan calls for trip­ling its 25 miles of trails to 75.

Af­ter a team formed in Austin this sum­mer, vol­un­teers helped cre­ate trails around the city so the kids would have a place to ride, said Austin coach Spencer Salm­on.

"Some of the resi­dents want­ed to build trails 10 years ago," but it nev­er got the city's sup­port, Salm­on said. This year, once it be­came known kids were going to be com­pet­ing, a plan was quick­ly put to­gether and 4 miles of new moun­tain bike track were built on land owned by Riverland Community College.

"You've got to have the trails to help feed and foster the pipe­line," Stillwater coach Annie Perkins said. "If it's there, peo­ple are going to do it. It's the whole chick­en and the egg thing."

Stillwater, the state's larg­est team with 60 rid­ers, doesn't have a "super great, close sin­gle track," to prac­tice on, Perkins said, but the team has made small cours­es at the high school fields, and they ride over stacked pallets and tires to work on tech­ni­cal skills.

Perkins said the sport has drawn Nordic ski­ers and down­hill rac­ers who use it for cross train­ing. The el­e­ment of dan­ger ap­peals to kids, too.

"They think it's cool," she said. "What's not cool about rid­ing in the dirt and rocks and ruts and it's kind of dan­ger­ous and you can skin your knee and you get blood?"

Sev­er­al rid­ers at Mankato's race talked about their own crash­es, most re­sul­ting in mi­nor scrapes. It's a chal­len­ging sub­ject for all high school sports: Some 1.4 mil­lion U.S. chil­dren were seen in an em­er­gen­cy room in 2012 for a se­ri­ous sports in­ju­ry while play­ing the 14 most com­mon high school sports, ac­cord­ing to data from the National Sport­ing Goods Association and the Con­sum­er Products Safety Commission. Perkins said that, at least in moun­tain biking, the goal isn't to take down an­oth­er ath­lete.

"You're com­pet­ing against your­self; yes, you're com­pet­ing against the team and the clock, but it's not like you want to kill the oth­er per­son. So we're not bang­ing heads," she said.

Draws all com­peti­tors

Grand­parents John and Gail Hill of Bloomington drove to Mankato over the week­end with grand­son Luke for Sun­day's race.

"I thought it was a good sport for him; you're part of a team but your score is your score," Gail Hill said.

Luke Hill, 13, said he joined the team this sum­mer, borrowing his sis­ter's mostly unused moun­tain bike. Soon he was navi­gat­ing hills at high speed.

"That's the funnest part," said the eighth-grad­er at Bloomington's Oak Grove Middle school.

John Hill stood at the base of Mount Kato as lycra-clad rac­ers sped past for an­oth­er lap up and over the ski runs and into the woods be­yond.

"It is amaz­ing," he said. "How would you like to ride over tree stumps?"

Matt McKinney • 612-673-7329