Gridiron To Iron Body

When Butch Johnson, 43, a receiver with the Dallas Cowboys and the Denver Broncos from 1976 to '85, competes in Saturday's Ironman Triathlon World Championship (2.4-mile ocean swim, 112-mile bicycle ride and 26.2-mile run) in Hawaii, he'll take part in "probably the hardest thing I've ever had to endure." From a man who survived Tom Landry's minicamps, those are strong words. Here's how the 6'1" Johnson's recent workouts and measurements compare with those during his NFL career.

Longest run

Football: 5 miles
Ironman: 18 miles

"The legs are the most important thing to a receiver, and they are the most important in the Ironman."

Longest swim

Football: 1,000-1,500 yards
Ironman: 5,000 yards

"You do it in intervals. People think football players don't swim. But it helps muscles other exercises don't touch."

Bench press

Football: Low reps, 300 lbs.
Ironman: 250 reps of 60-100 lbs.

"When I was a player, I'd do heavy weight. I wanted to be big. Now it's about toning. "