Steve Faust once tackled a 140-mile run through the jungles of Costa Rica, essentially completing a marathon a day for six days.

Faust, a co-owner of Sharon Center Veterinary Hospital, also tried running Alaska's Iditarod trail in February 2002 while pulling a 35-pound sled. But the 40-year-old son of former University of Akron and Notre Dame football coach Gerry Faust only made it 68 miles, 32 short of the finish.

Doug Klein, a 46-year-old CPA at SS&G Financial, has run about 15 marathons in the past nine years, including three Boston Marathons. At least eight of those have been with Faust.

That doesn't make their plan for Sunday sound any less daunting, especially to those who believe a perfect weekend means never leaving the couch.

If all goes well, Faust and Klein will run nearly 60 miles, including the last 26.2 in the Rite Aid Cleveland Marathon.

They expect to leave Klein's house in Fairlawn between 12 and 1 a.m. and follow the Ohio
and Erie Canal Towpath Trail for 32.4 miles. They want to reach the marathon's starting point at East 13th Street and St. Clair Avenue at least an hour before the 7 a.m. start.

Faust then hopes to finish the marathon in less than four hours. Faust, a resident of Sharon Township, ran Cincinnati's Flying Pig Marathon in 3:20 two weeks ago.

''I'm running the half-marathon, but I'm not involved in this insanity,'' said friend Bill Mann of Medina.

Just a step

The endurance test Sunday is part of the pair's training for the Burning River 100. The second annual 100-mile run, which has a 30-hour time limit, starts in Willoughby Hills on Aug. 2 and ends in Cuyahoga Falls on Aug. 3. Klein and Faust participated last year but didn't finish, running side by side for 60 miles, personal records for both.

''It's a war of attrition for the body,'' Faust said of the Burning River. ''Your knees and feet are screaming at you. It was 90 degrees. I was emotionally torn to shreds.''

Klein said of that run, ''Last year we were kind of testing it. This year we're pretty serious about getting it done. The biggest thing is can I stay awake for 30 hours?''

Klein conceded that he might not even make it through the challenge Sunday without a cup of coffee before the marathon. Going out that early in the morning will not bother Faust, who does a lot of his training in the dark.

They will be equipped with LED headlamps, along with a GPS on Faust's wrist, at least a couple of bottles of Gatorade apiece and power bars made by Klein's wife, Anita. They'll shed all that and change shirts, shoes and socks when they meet their friends and spouses, including Faust's wife, Pij, in downtown Cleveland.

Marathon and more

In Cincinnati, Faust was thrilled to qualify for his second Boston Marathon, completing a 41/2-year quest that came in between the birth of his two children. Both he and Klein are attracted to the longer distances and ultras (generally 31 miles but sometimes 50), especially trail running.

''Technically it's a lot harder because you have to navigate routes and hills and holes and ruts and streams and downed trees. You're not running on the road and keeping a constant tempo,'' Faust said. ''It's easier on the body. I like to be in the woods.''

Klein enjoys the scenery but appreciates it more for the camaraderie.

''We got acquainted with some virtual runners, and they're all into trail running, off-road,'' Klein said. ''Back in the woods, everybody's helping everybody.''

The adventure Sunday will be a far cry from Costa Rica, which Faust did last year.

''They wouldn't let you run at night because of all the jaguars,'' he said. ''At the camps there were howler monkeys, iguanas and sea turtles. I didn't see anything scary, just a few snakes. I like Latin America. I used to live there.''

Klein followed his wife into running. He worked for the Internal Revenue Service in Cincinnati, and they had no children when Anita Klein received a card in the mail from the Leukemia and Lymphoma Society promising, ''You can go from the couch to running a marathon in 16 weeks.''

She raised $2,000 and the society paid for her airfare and entry fee for the inaugural Rock 'n' Roll Marathon in San Diego in 1998.

''It was a life-changing experience for her,'' Doug Klein said. ''We started running together, now we've got over 30 marathons between the two of us in less than 10 years.''

All in the family

Their son Christopher, 6, runs with the Fausts' daughter Alex, 5.

''On Sundays they run a mile or two to Sand Run Park, go to the creek and play,'' Klein said.

Klein's and Faust's friendship was born with a strange twist. Before they had Christopher, the Kleins kept ferrets, and Faust was Anita Klein's veterinarian, whom she called Dr. Steve.

''A guy showed up from time to time to run, but he usually works on Saturday,'' Doug Klein said of their running group. ''Steve was there once, and someone said, 'Why don't you run with him, he's the fastest.' So I chased after him.

''There were four of us, me and Steve, my wife and his wife Pij at a New Year's Eve race. Steve said to Anita, 'What are you doing with this guy?' and she said, 'This is my husband.' We became fast friends. We've run eight to 10 marathons in the last four or five years, including some ultras.''

Ultra training

This ultra was needed in their training for the Burning River. But Klein figures their families and time constraints might preclude another.

Faust sounded borderline diabolical when that notion was suggested.

''We'll be doing more than this,'' Faust said. ''He doesn't know it yet. I make the schedule.''