Civil Engineering Reference
In-Depth Information
Injury Rate
Risk Assessment
12
100
90
80
70
60
50
40
30
20
10
0
10
Risk
Category
Change
8
High-High
High-Med.
6
4
High-Low
2
0
After
Before
After
Before
Job Intervention Status
Job Intervention Status
FIGURE 49.4 The impact of job interventions on LBD risk assessments and LBD injury rates, using the iLMM, for
three groups. The “high-high” group indicates those jobs where LBD risk remained high following a job change. The
group of “high-medium” jobs were those whose interventions produced a moderate drop in LBD risk. The “high-
low” category included those jobs where the intervention resulted in a large reduction in LBD risk. These charts show
that, on average, changes in a job's resulting risk assessment level following an intervention were positively correlated
to the job's LBD injury rate.
groups of jobs whose interventions produced an LBD risk assessed as “low” resulted in an average injury
rate drop of approximately 85%.
A concern in the assessment of jobs having a high LBD risk is the possibility that employees having had
a back injury, or currently experiencing low back pain, may move differently than those with healthy
spines. This could influence their trunk kinematics and the resulting risk assessment for a job using
the iLMM. However, Ferguson et al. (in review) found this concern to be unfounded. They studied
200 employees who had returned to their jobs following a low back injury, as well as 200 controls
having no reported low back pain who were experienced performing the same jobs. These individuals
all were monitored at their worksites while wearing the iLMM. The data showed no statistically signifi-
cant differences between those two groups of employees on any trunk motion measures. Further, the LBD
risk assessments using the iLMM also did not differ between these two groups.
These results support the use of the iLMM and the LBD risk model as an accurate method for deter-
mining a job's potential to produce low-back injuries in employees performing the work. It also has been
found to be predictive, in that risk level changes arising from job interventions were positively correlated
with actual changes in LBD injury rates.
49.4 Benefits of the iLMM and the LBD Risk Model
Use of the iLMM and its computation of LBD risk provides several advantages to those assessing injury
risk for material handling activities. First, the iLMM can determine the instantaneous three-dimensional
position, velocity, and acceleration of the trunk while individuals perform their actual job tasks, not work
simulated instead in a laboratory or artificial work setting. This ability eliminates any question of differ-
ences between trunk motions gathered in simulated work environments from those actually obtained on
the job. Also, the quantitative iLMM data are objective. Trunk motions and the resulting calculations of
LBD risk are determined irrespective of an investigator's (perhaps unintentionally biased) view of
the work.
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