Tom Green is not your average house painter. In two decades, Green, who is 52 and from Columbia, has competed in more than 150 ultra-marathons - footraces from 30 to 100 miles long. That's in addition to about 40 marathons.

Green raced on the cross country team at Concord College in West Virginia in 1968 and 1969 and advanced to the 10- kilometer and 26.2-mile marathon circuits. Seeking more of a challenge, he said, he began ultra racing at age 33.

He will be at it again Saturday in the annual JFK 50-miler that starts in Boonsboro and ends in Williamsport, with a long stretch on the Appalachian Trail.

This will be his 13th JFK - arguably his 14th because he and a friend once did the course in each direction - back-to-back.

Last month, Green completed his 20th Mountain Masochist 50-mile run in southern Virginia and was honored as the only competitor to have run in all of the event's 20 races.

We asked the running man to talk about his avocation.

What is it about running that you like so much?

It's changed over the years. I originally got into it more for the competition and the challenge. Now it's evolved more into a social aspect.

So, if I don't go, I don't see my friends. You see the same runners, no matter where you go anywhere in the country.

How do you stay motivated to finish a race that is so long?

The whole key is mental preparation and realizing exactly how long you're going to be out there. If you go into a race knowing that you're going to be out there for 24 to 30 hours, then you're not as likely to lose your motivation after 12 hours.

Do you do anything in particular to mentally prepare?

You try to visualize running the course, being in the race, knowing how bad you're going to feel. That helps when ... you're sick or you're tired or you're hurting. You've basically accepted that it's going to happen. So, you'll be less likely to drop out.

How much time do you devote to running in a typical week?

I may only get out three or four times a week for a one- to two-hour run. So maybe five to six hours a week tops.

What is your running season?

I generally take a break during the winter. It's hard to maintain your peak conditioning 12 months out of the year. You do want to train more specifically for a season when most of the runs are.

In marathoning, people talk about "hitting the wall" - typically physical and mental exhaustion that occurs around 18 miles into the 26-mile events. Do you hit a wall in an ultra-marathon?

Absolutely. And it comes at about the same percentage into the race. If you are running a 50-mile race, it seems the most difficult part would be somewhere in the neighborhood of 38 to 40 miles. In a 100-mile race, it's getting beyond the 75-mile and 80-mile point.

Do you have a special diet?

I don't do anything different than what I probably would be if I wasn't running. But I've been running for so long, I don't know what that would be.

What is the scariest thing that has ever happened to you during a race?

I ran the Western States 100-miler [which starts in Squaw Valley, Calif.] a few years ago. And before that race, a woman had been killed by a cougar on the same trail.

We ran through that same spot in the middle of the night. When you're by yourself with a flashlight, your mind really starts to imagine that you're seeing and you're hearing things.

Do you have any favorite event?

I like different events for different reasons. I really enjoy the 100-mile trail runs, just for the vast degree of challenges that you have along the way, from navigating, running by flashlight, having to carry your equipment, the footing and all of that.

I also enjoy the 24-hour run, which is laid out on a perfectly flat, paved loop. Of course, the shorter runs, like the 50-milers and the 50-kilometers, they're just enjoyable.

How would you advise anybody who might be interested in running ultra-marathons?

People have a misconception that ultra-marathons are far more difficult than a marathon. It's not true.

Anybody who could run a marathon can just as readily get through a 50-miler. It's just a matter of pacing. The only difference is the mental aspect, obviously. You don't hurt any worse; you just hurt a lot longer.

How long does it take to finish a 50-mile or a 100-mile race?

It depends on the course, but generally on a 50-mile trail run these days, I'm pushing 10 hours, and 24-30 hours for 100 miles.

How much longer do you think you can do this?

I'm hoping to be running at least another 20 years. But it gets harder and harder. I may have to cut back on the 100-mile runs and just be satisfied with the 50 miles.