Measuring posture for epidemiology: Comparing inclinometry, observations and self-reports

Abstract

The objective of this study was to use and evaluate three postural assessment methods for epidemiological studies of back disorders. The methods were: (1) a data-logging inclinometer; (2) observations by trained observers; (3) self-reports by employees. All methods were feasible in 50 heavy industry worksites. Inclinometry provided quantitative measures of flexion-extension (mean 17 degrees, SD 11.2 degrees), lateral flexion (mean 8.5 degrees, SD 2.6 degrees) and trunk movement speed (mean 14.3 degrees per second, SD 4.9 degrees per second). Observations and self-reports provided estimates of time spent in various trunk angles, general postures, materials handling and vehicles. Compared to observations, self-reports under-reported less common tasks, but over-reported task durations. In statistical modelling to determine if observations or self-reports could be used to estimate measured postures, observations accounted for 30 to 61% of the inclinometer measurement variance and self-reports for 33 to 40%. A combination of inclinometry and observations would be an ideal option to provide both depth and breadth of data on postures and other physical exposures for epidemiological research.

Cost-efficient assessment of biomechanical exposure in occupational groups, exemplified by posture observation and inclinometry

“…This is rarely done in occupational epidemiology, probably because the extent of bias is unknown, especially in studies addressing only one exposure assessment method. The status of inclinometry as "best performer" in the present case is due entirely to the a priori decision to designate inclinometers as giving "correct" data, which is standard in occupational studies (38,49,50). If observations were designated as the method producing correct results from which to calculate bias, the observation method would have had better relative performance than inclinometers when bias and precision were combined.…”

“…For the upper arms, the zero position was to bend forward and hold a 5 kg weight in the hand. The trunk's reference positions involved bending forward (to define "forward") and then standing upright (to define zero) as described in Teschke et al (38). The raw three-axial data from the inclinometers were calibrated and transformed into degrees by using the same software used by Wahlström et al (39) and Hansson et al (28).…”

Evaluation of four sensor locations for physical activity assessment

“…Methods for assessing exposure to nonneutral working postures in a field setting include self-report, observational, and direct measurement (Burdorf and Van Der Beek, 1999;David, 2005). The standard approach for directly measuring occupational exposure to non-neutral postures of the low back and shoulder is with piezoresistive accelerometers or, more recently, inertial measurement units (IMUs) secured to the trunk and/or upper arms (David, 2005;Li and Buckle, 1999;Teschke et al, 2009). …”

The Effectiveness of a Lumbopelvic Monitor and Feedback Device to Change Postural Behavior: A Feasibility Randomized Controlled Trial

“…39,51,57 Previous studies have used a variety of devices for postural monitoring. 4,13,18,48,58 A common problem found in postural-monitoring devices used during daily activities is the trade-off between portability and accuracy of measurements.…”