But on football fields across Denver, hundreds of pro athletes are already in game mode.

"You have to pick things up pretty quickly," Jackson McClellan, who's in his rookie season with the Blue Knights Drum and Bugle Corps said. "You just kind of have to jump in."

McClellan, a horn player, is from Boulder.

He is taking lessons on endurance from all of the veterans of the Blue Knights.

The ensemble is getting ready for Colorado's biggest marching music competition, Drums Along the Rockies.

"I thought there'd be a little bit of a learning curve," McClellan said. "But you just kind of have to jump in."

Many of the Blue Knights performers come from all over the country to perform with one of the most elite marching music ensembles in the nation.

And for anyone who has seen a Drum and Bugle Corps performance, you know, it can simply take your breath away.

"You really feel it," said Amber Connolly, a color guard member. "All the way through your body."

Many of the Blue Knights' members have to train hard to catch their breath during practice.

"They're athletes," said Mark Arnold, director of the Blue Knights.

The corps practices upwards of 12 hours a day.

"We're always, always, always on the move," drum major Angelo Sapienza said. "These kids are burning about 8 to 10,000 calories a day."

They eat together, sleep in school gyms, and travel on tour buses to competitions across the nation.

"I think the simplest way to put it is marching band on steroids," Sapienza said.

"This is for those kids who choose music to excel," Arnold said. "We want them to strive to be the very best they can in music."

The Blue Knights will compete July 7 at Drums Along the Rockies, Colorado's premier marching music event.

Drums Along the Rockies takes place at 6:30 p.m. at Sports Authority Field at Mile High with some most elite ensemble groups in the nation performing.

To purchase tickets, visit: http://ascendevents.bknights.org/PurchaseTickets.aspx

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