Back pain is second only to the common cold as the nation's most prevalent affliction. Stress, sedentary lifestyles, poorly designed work sites and expanding waistlines all contribute to America's back problems. But government experts also say improper methods of lifting play an important role.

"We have lots of people out there lifting heavy things," notes David Cochran, a University of Nebraska ergonomist who is currently working at the Occupational Safety and Health Administration (OSHA). Jobs at high risk for lifting-induced back pain include health care workers who lift patients, baggage handlers, construction workers, retail clerks, mechanics and delivery people.

Many factors are involved in back strain from overexertion, which accounts for an estimated one-fourth of all workplace injuries. Loads may involve awkward placement or poor ergonomics or may simply be too heavy for one person to carry. But often, injuries occur when people use poor lifting technique.

OSHA experts offer these guidelines to help avoid lifting injuries:

* Bring the load as close to your body as possible before you lift. If you're lifting a person from bed, have him or her get as close to the edge as possible first. Consider purchasing a special belt with hand grips (available at home health supply stores) to lift people who are frail.

* Recognize that lifting below knee height or above shoulder height is more strenuous than lifting between these points. Adjust the height of the object you're lifting, if possible.

* Bend your knees to a comfortable degree. Since leg muscles are stronger than back muscles, it's better to bend and push off from the knees than from the waist.

* Separate your feet, putting one slightly in front of the other when you lift.

* Avoid twisting your body when carrying a heavy load.

* Make sure the load is balanced and even.

* Move slowly and evenly, avoiding fast, jerky movements.

* Remember that setting the load down properly is just as important as picking it up. Bend your knees and use your leg and back muscles to comfortably lower the load.

* Avoid carrying a load above your head or on the side of your body.

* Use caution and forethought to plan your lift--remove any obstacles in your way and know where you're going to set the load down.

* Consider using a device, such as a dolly or cart, or another person to help lift heavy items.

* Don't rely on a back belt to protect you from injury. "A back belt is not a personal protective device, even though some people seem to think it is," says OSHA ergonomist Gary Orr. While the belts may have some effect in helping avoid injury, he says, "the biggest benefit may be from the training [in proper lifting techniques] that people receive with the belt."