STEP-CHILD OF THE GYM: Stepping machines are a well-kept secret Picture: GALLO/GETTY IMAGES

'Competitive stair climbing pounds my legs and knees substantially less than running'

Maybe that is because whether you call it a stepper, stair climber or stair mill, it evokes the drudgery of Sisyphus, the character in Greek mythology condemned to push a boulder uphill for eternity.

But experts say if you master the stairs, you will reap dividends in tight abs, butt and thighs.

"It's the intensity," said Kerri O'Brien of Life Fitness, which designs and manufactures exercise equipment.

"There's a vertical component. You're going to be working harder because you're going against gravity. Also you'll have isolated muscle soreness because you're using muscles you're not used to using."

But if done regularly, O'Brien - an exercise physiologist - said it would become more enjoyable.

It is also a great workout for the muscles that make up the buttocks.

Staircases have been around almost from the beginning of civilisation. In 2004, archaeologists found a staircase in Austria believed to be at least 7000 years old.

O'Brien said modern steppers evolved from so-called Jacob's Ladders, climbers prevalent in high school gyms of the '50s. "And ever since the '50s, football and track teams have used running up stadium stairs to work out. People also use step climbers to train for mountain climbing and hiking."

It is also an effective low-impact cardio choice. A British study found that daily stair climbing among sedentary young women resulted in a rise in HDL, or good cholesterol.

Dr Hank Williford, of the American College of Sports Medicine, said steppers were a good fit for women.

"They're not bouncing around like with a treadmill and still they can increase their bone marrow density and prevent osteoporosis," he said.

It is also more effective for burning calories than stairs. "In regular going up and down stairs, the energy cost is one-third going down versus going up. With steppers you do not go down the steps; you just keep going up," Williford said.

Michael Karlin, a lawyer in New York, started using a stair climbing machine to lose weight and wound up scaling all 1576 stairs of the Empire State Building.

Stair climbing races are held worldwide. The American Lung Association alone holds 57 in stadiums and skyscrapers throughout the US.

"I competed in the Empire State Building climb last year, finishing in 16 minutes, 3 seconds," said Karlin. "I have derived tremendous benefit," the 38-year-old said. "My legs are really strong, my sprinting has improved, and my lung capacity is much greater. Competitive stair climbing pounds my legs and knees substantially less than running."

So how would Karlin feel about French writer Albert Camus's essay suggesting that Sisyphus was happy in his uphill struggle?

"I love preparing for a race, finishing the race, and talking about it!" Karlin said. "Doing the race itself, though, well, that really hurts."