Charles Bauer has been running for 25 years, ever since he decided he needed more physical activity and got bored with a treadmill.
But the 78-year-old Timber Pines resident did most of his running on flat surfaces.
So he was concerned about the Sheriff's 5K Challenge, a cross-country race that will debut Saturday at the Sand Hill Scouts Reservation on State Road 50, west of Brooksville.
As of Tuesday, Bauer was the oldest of 49 runners who pre-registered. Race director Deputy Cinda Moore hopes to have another 50 to 100 by Saturday.
Before he would commit, Bauer needed an answer from Moore.
"I said, "Tell me. At my age, I'm not interested in busting myself up here. Is this going to be an obstacle course?"' Bauer said.
"She assured me it was not an obstacle course. Because if it was, it's not for me."
Hernando County Sheriff Richard Nugent, an avid runner, created the race when he needed to raise funds for the county's Harmony in the Streets summer program.
The two-week program allows troubled children to interact with law enforcement officials and learn skills such as conflict resolution.
"The sheriff wanted to do something to help out," Moore said. "This was one of the ways he wanted to do it."
Runners can pre-register online at www.active.com through Thursday or by completing an application at the sheriff's office. Cost is $12 in advance and $14 at the race.
Most registrants are from Hernando, Citrus or Pasco counties. Andy Riddiford, of Upchurch, England, decided to extend his vacation to participate.
Successful masters runner Al Treichel, 72, of Spring Hill also registered. Thirty-one-year-old Jennifer Schmidt, one of Citrus County's top 5K runners, is a possibility.
Registrants are as young as 12-year-old Taylor Tedesco of Dade City and as old as Bauer.
The retired doctor from Buffalo, N.Y., started running in his 50s because he felt sluggish and wanted exercise.
He joined a spa and worked out on a treadmill but quickly found he preferred running outdoors.
His favorite memories are of the YMCA Turkey Trot in Buffalo, which attracts close to 5,000 each Thanksgiving. He has competed about 15 times, winning his age group on several occasions.
He runs about 20 miles a week, down from 30 to 35 when he was younger.
As he aged, his mile time increased from under seven minutes to close to nine.
He will be happy to maintain a 10-minute pace on Saturday, considering the uneven terrain.
"I said to (Moore), "I hope you've got all the roots and the stones and the other stuff cleaned up,"' he said.