Fitness junkies are used to having relatively open access to Red Rocks Amphitheatre’s many steps and benches for morning workouts, but the city of Denver just announced a private fitness program that will close the amphitheater to the nonpaying public for more than an hour once each week, starting Saturday.

The HealthOne Red Rocks Fitness Challenge will close the popular mountain amphitheater once a week, mostly on Saturday mornings between 7 and 8 a.m. The event costs participants $150 for the season and provides them with personal trainers (assigned to groups), medical experts and workout regimens, according to Red Rocks’ website.

The site says Red Rocks sees more than 500,000 visitors each year who specifically head to Morrison for the fitness scene — hiking, biking, running and training in and around the storied space.

Denver-based personal trainer Christopher Flower is one of those people, and he’s not pleased that the city-owned, open-to-the-public venue will be closed during such busy hours.

“Saturday mornings are prime time for anyone, not just trainers, who wants to go up there for a workout,” Flower said Thursday. “Red Rocks is so great because it doesn’t have to be extreme fitness. A hike, a walk, a run — all of that’s great, and cutting into our time up there on a Saturday or Sunday morning, when people don’t have to work, that’s just too bad. I hate to hear that.”

The city hasn’t heard much push-back from the community, according to Kristin Rust, communications and marketing director for Arts & Venues Denver, the city agency which operates Red Rocks.

“We’re doing all we can to get the word out so people can plan,” Rust said via e-mail. “We tried to keep it quite early (because) it is very popular around 8 a.m.”

Early-rising nonparticipants will be asked to clear out of Red Rocks at 6:30 a.m. on the specified days, Rust said. The venue’s top entrance will be the only open gate between 6:30 and 8:10 a.m. on those days, and participants in the HealthOne Red Rocks Fitness Challenge will check in with their wristbands. Nonparticipants will be allowed into the park after 8:10 a.m.

Park limits

For a complete list of closings, visit blogs.denverpost.com/travel/