He died Thursday at his home in Clifton, N.J., his son Gerald said.
Staub, a mechanical engineer, built and marketed his first treadmill in the late 1960s — 40 steel rollers covered by an orange belt, a grey cover over the motor, and orange dials to determine time and speed. Staub envisioned it as a tool for people who wanted to run or walk outside but didn't because of inclement weather, less-than-ideal circumstances or creative excuses, his son said.
At the time, the treadmill was almost exclusively used by doctors, said Dr. Kenneth Cooper, a health and fitness pioneer who used the machine to perform stress tests. William Staub, who didn't exercise at the time, read Cooper's 1968 book "Aerobics," which espoused the health benefits of exercise.
"Dr. Cooper said if you ran a mile in 8 minutes and did it four to five times a week, you would always be in a good fitness category," Gerald Staub said. "He said even I — no excuses — I can afford 8 minutes. That's what excited him about it."
The book mentioned a treadmill, and William Staub wanted to develop it commercially so people could run their 8-minute miles indoors.
"The treadmills we were using were very expensive, but there wasn't one on the market for the masses. And that's why he said, 'We need this,'" Cooper said. "I encouraged it. I said, 'If you can develop a treadmill that could be used in a home or an apartment it would be a slam dunk.' And it was."
But not at first. Gerald Staub remembers having conversations with his father in which the two hoped to sell 10 or 12 treadmills a day. The machine was a curiosity at trade shows because few had ever seen or heard of a treadmill.
"Some people couldn't pronounce it. They would call it a threadmill," Gerald Staub said. "I would joke and say we were helping people get no place quickly."
At the time, William Staub owned an aerospace company called Besco but soon focused on selling his treadmill, the PaceMaster, through a company he called Aerobics Inc. William Staub sold it to Gerald and another son in the 1990s, and the company folded in 2010.
"I don't think he thought it was going to be quite as big as it was," Gerald Staub said.
Barbara Bushman, a professor of kinesiology at Missouri State University, said William Staub changed the way people exercise.
"From a public health standpoint, it's so encouraging. He really took away the excuse of the weather's not conducive to exercise today," Bushman said. "The neighbourhood conditions are not safe or optimal; it's early morning. All those excuses are really taken away with one piece of equipment."
Staub was born in Philadelphia on Nov. 3, 1915. His wife, Dorothy, died in 2007, and a daughter in 1977. Survivors include four sons and two daughters.
Staub was fastidious about his diet and ate the same lunch for years at a time; tomato soup, toast and tea for a while, then a tomato sandwich with a slice of cheese and lettuce, Gerald Staub said. He was a lifelong bowler who once owned a bowling alley and loved to water ski and build model airplanes.
And he became a lifelong devotee of the treadmill.
"I saw him on the treadmill just a couple months ago," Gerald Staub said.