Industrial Lumbar Motion Monitor - Fundamentals and Assessment Tools for Occupational Ergonomics - page 946

FIGURE 49.2 The iLMM's three-dimensional calibration and reference frame.

workplace factors associated with each of these jobs; and (4) evaluate the data, to determine which com-
bination of gathered factors best distinguished between the high- and low-rate groups.

49.3.2 Study Design
This was a cross-sectional study of 403 industrial jobs from 48 manufacturing companies throughout the
midwestern United States. Only repetitive jobs without job rotation were examined in this study. This
was necessary to prevent the confounding effects created by alternating jobs. Jobs examined in this
study were divided into two groups — having either high or low LBD rates — based on an examination
of the company's injury and medical records. Whenever possible, company medical reports were used to
categorize these rates, but in some cases only injury logs (i.e., OSHA 200 logs) were available. All medical
reports, injury records, and logs were scrutinized to ensure they were as accurate as possible. The
outcome measure derived from these records (LBD rate) consisted of the normalized incidence of

TABLE 49.1 Correlations of the Velocities and Accelerations of the
Motion Analysis System in the Three Planes of Motion with the
Velocities and Accelerations of the iLMM

Correlation

Plane Velocity Acceleration

Lateral 0.95 0.95

Sagittal 0.99 0.96

Twisting 0.99 0.99

p , 0.0001.