PURPOSE:  Reduce musculoskeletal disorders among operators of mobile equipment.

RESEARCH SUMMARY:  A recent estimate shows there are approximately 540,000 operators of heavy equipment (i.e., dozers, loaders, haul trucks, etc.) in mining and construction in the United States and this number is expected to increase. Operators of mobile equipment perform various duties that expose them to a variety of risk factors in the work environment, such as whole-body vibration, awkward postural requirements, repetitive motions, poor seat design, and poorly designed cabs or controls, all of which have the potential to cause injury and expose operators to the risk of developing musculoskeletal disorders. Musculoskeletal disorders - including most sprains and strains - are the most common type of nonfatal injury in mining. In addition, loss of postural stability and improper egress are significant factors in fall injuries among these operators.

Mine Safety and Health Administration (MSHA) data show that between 1999 and 2003, 4079 accidents in surface mining were classified as back injuries and contributed to nearly 173,000 lost or restricted work days (an average of 42 days lost or restricted per accident). Truck drivers (n = 535), dozer operators (n = 467), and front-end loader operators (n = 409) alone accounted for over one-third of these injuries. Another 6060 accidents during this same period were classified as injuries caused by overexertion and affected truck drivers (n = 539), dozer operators (n = 508), and front-end loader operators (n = 358).

The specific aims of this project are to (1) evaluate the ergonomic design of cabs and egress from and entry into cabs, (2) estimate the landing force required to exit mobile equipment, (3) characterize exposure to whole-body vibration at the seat/operator interface; (4) evaluate the effects of whole-body vibration on operators’ postural stability; and (5) collect work and health questionnaire data from operators of heavy mobile equipment as part of an epidemiological survey.

Some of the significant outcomes will be (1) field tests of the effectiveness of a device to reduce low back discomfort among operators of mobile equipment, (2) evaluations of cab design of mobile equipment, (3) a better understanding of the prevalence of musculoskeletal symptoms and psychosocial factors affecting operators of construction equipment, (4) evaluations of postural stability after exposure to whole-body vibration and development of recommendations for control, and (5) evaluations of landing forces as operators exit equipment and development of recommendations for control.