Occupationally-related low back disorders (LBDs) are the leading cause of lost workdays and the most costly occupational safety and health problem facing industry today. LBDs are particularly prevalent in manufacturing, distribution center, and warehousing environments where repetitive lifting is common. Although assessments have successfully evaluated LBD risk during a single exertion, none have been able to effectively assess how risk changes during repetitive lifting at various lifting frequencies throughout a workday. This study will assess how exposure to different frequencies of lift over time can result in unacceptable biomechanical risk of LBD. Our preliminary studies point to two mechanisms of risk. First, different lift frequencies affect lifting kinematics and the subsequent muscle recruitment patterns. These changes alter the nature (direction) and magnitude of spinal loading, thereby exceeding spine tolerance limits. Second, exposure to a repetitive lift throughout the workday can also result in muscle recruitment pattern changes over the work period, thereby, increasing the spinal loading throughout the day. Hence a lift frequency that is acceptable early in the workday may exceed biomechanical tolerance limits as the workday progresses. This study will explore the changes in muscle recruitment and spinal loading when workers lift one of three weights (corresponding to the range of industrial exposures) at six different lift rates over extended workdays. The frequency and duration of lift will be judged risky and unacceptable when the spinal loads exceed documented spine tolerance limits. These findings will result in an understanding of the portion of the population at risk for spine structure (disc) injury as a function of load magnitude, lifting frequency, and lift period duration. These results will provide quantitative guidance for the mediation of work-related LBDs for the millions of workers performing materials handling tasks in manufacturing and distribution center environments.

Agency
National Institute of Health (NIH)
Institute
National Institute for Occupational Safety and Health (NIOSH)
Type
Research Project (R01)
Project #
5R01OH003913-04
Application #
6683317
Study Section
Safety and Occupational Health Study Section (SOH)
Program Officer
Frederick, Linda J
Project Start
2000-09-30
Project End
2005-09-29
Budget Start
2003-09-30
Budget End
2005-09-29
Support Year
4
Fiscal Year
2003
Total Cost
$147,500
Indirect Cost
Name
Ohio State University
Department
Engineering (All Types)
Type
Schools of Engineering
DUNS #
071650709
City
Columbus
State
OH
Country
United States
Zip Code
43210