Inside NIOSH:

Lift-assist system has baggage handlers’ backs

For travelers, restrictions on baggage weight may mean packing fewer pairs of shoes. For airport baggage handlers, weight restrictions, combined with proper lifting, are important to safety and health but may not be enough to prevent work-related back injuries.

Compared to other occupations, baggage handling has the third-highest rate of musculoskeletal injury, according to the most recent figures from the Bureau of Labor Statistics. Previous studies show that most of these injuries involve the back. One way to prevent back injury is by using mechanized lift-assist systems, but little information is available about their effectiveness in reducing biomechanical risks of back injury among baggage handlers.

To look at the issue, a NIOSH investigator and researchers from the Ohio State University tested a vacuum lift-assist system in the laboratory and simulated baggage-handling tasks similar to those that typically occur in the ramp area of an airport. Study participants included eight males and two females with an average age of 26. They lifted baggage that weighed 14.5 kilograms (31 pounds), the average for travelers’ checked-in baggage, from a conveyor belt to a two-shelved baggage cart and back. Using a special research technique to record the electrical activity levels of many back muscle groups during lifting, the investigators estimated the level of compressive and shear forces acting on the spine. They compared the effects of manual lifting to the effects of lifting with a commercial lift-assist system, which has the capacity of lifting a load up to 50 kilograms (110 pounds).

The study found that the lift-assist system significantly decreased the amount of spinal loads to workers’ backs when lifting baggage. Specifically, it decreased compressive forces (i.e., top down force compressing on the spine) on the lower back by 39%, and the shear force (i.e., lateral force from the front to the back) on the spine by 25%, according to the study published in the journal Applied Ergonomics. In addition, the study found that the greatest back strain occurred when lifting baggage to the top shelf of a baggage cart. These findings show that lift-assist systems could help prevent back injury among baggage handlers, particularly when loading baggage to these top shelves.