Ask the average dog owner who they rely on more, their dog or a human friend, and many will say their dog.

Now there's a study to prove that four-legged friends are more reliable than two-legged ones.

University of Missouri researchers found that people who walk dogs are more consistent about regular exercise and showed more fitness progress than those who walked with a human companion, according to the New York Times.

A 12-week study of residents of an assisted living facility looked at 35 walkers, of which 23 selected a friend or spouse to walk with them and 12 took the bus to a local animal shelter to walk dogs.

Researchers were surprised to see the dog walkers getting a big boost in fitness levels, while the human walkers began making excuses to skip the workout. Walking speed among the dog walkers increased by 28 percent, compared with just a 4 percent increase among the human walkers, the Times reported.

"What happened was nothing short of remarkable," said Rebecca A. Johnson, a nursing professor and director of the Research Center for Human Animal Interaction at the University of Missouri's College of Veterinary Medicine. "The improvement in walking speed means their confidence in their walking ability had increased and their balance had increased. To have a 28 percent improvement in walking speed is mind boggling."

It was the human companions who were the biggest drag on improvement, the study found.

"In the human walking group, they were regularly discouraging each other from walking," Johnson said. "Missouri is a hot state. We would hear them saying: 'It's hot today. I don't want to walk, do you?' "

Need we report how the dogs reacted to the Missouri heat? At the drop of a leash, the dogs were always raring to go.

Dog walking even helped some participants abandon their walkers and canes. Johnson said that some of the dog walkers made such improvements during the study period that they reported they were fit enough to take their dogs for a walk without assistance.