WHEELING - During the Hawaiian Ironman triathlon, scuba divers wait underwater at the race's start - just in case a swimmer gets knocked out or shoved below the surface by another competitor.

Dr. Joseph Maroon has experienced such a start. In past races, his goggles were smacked off his face and he's had people swim over top of him to get ahead.

Maroon, originally from Bridgeport, is vice chairman of the department of neurological surgery at the University of Pittsburgh School of Medicine and team neurosurgeon for the Pittsburgh Steelers.

Maroon, 68, finished in the Top 20 for his age division during the October triathlon in Kona, Hawaii. He's competed in five other Ironman races, and 50 triathlons, or swim-bike-run competitions, during the past 20 years.

When he is preparing for competition, the workouts are grueling. But in the end, they payoff. It prepares him not only physically, but mentally to compete with some of the world's fittest athletes. And often, such as the start of a 2.4-mile swim against ocean waves, it's a matter of survival.

The Ironman is intimidating and exhilarating, he noted.

''The bike is 112 miles, but in 90-degree heat. It's like driving from Bridgeport to Zanesville and back, but on a bicycle. And there is heat radiating from lava fields,'' Maroon said.

The terrain is far from flat. At the midway point, the cyclists are forced to traverse a volcano. During the 26.2-mile marathon, Maroon ran by moonlight because there were no streetlights outside the city limits. And at the end of it all, his shoes were ''full of blood.''

''I had blisters on both feet. ... It was terrible,'' Maroon said, noting it was difficult for him walk several days after the race.

Some may wonder why anyone would want to punish their body the way a triathlete does. For Maroon, the feeling he gets can be compared to what often called ''the runner's high.'' It's that moment when the mind and body is stretched to the limit, but the athlete still perseveres, he said.

''The experience for me is one of the best feelings in the world, and that type of commitment helps in my neurosurgical practice,'' Maroon said. ''I'm much sharper, I'm more patient and tolerate. It has helped me be a better neurosurgeon.''

His surgeries can last from a hour to 12 hours.

Maroon said for now his body is recovering from the Hawaii race. But this summer he may compete in a half Ironman in Munci, Ind.

''I actually look forward to turning 70. I'll be in a new age group. I think I'll be more competitive at that age,'' he said.

He noted in November 2007, his left knee had reached the point of needing surgery.

However, Maroon opted for an experimental procedure that involved injecting stem cells taken from his own hip marrow into his knee. Though ''not quite a new knee,'' the procedure, performed by Dr. Chris Centeno in Colorado, allowed him to compete in Hawaii.