The effect of theory-based educational intervention on correct principles of manual material handling among men

BACKGROUND

Changing human behavior for the purposes of improving the way people work is an integral part of most educational interventions. This study aimed to evaluate the effect of a model based on the theory of planned behavior (TPB) on correct principles of manual material handling (MMH) among male soldiers.

SUBJECTS AND METHODS

This study was a quasi-experimental, pretest-posttest research with a control group. Furthermore, 140 soldiers, from an area located in the city of Bandar Abbas, Iran, were selected through a simple random sampling and they were divided into two groups: intervention and control (70 subjects in each group). The data were collected using a three-part questionnaire including demographic information, the theory constructs, and MMH behavior. The intervention group was given the relevant education, and after 2 months, the both groups were evaluated.

RESULTS

Based on regression analysis, attitude toward behavior and perceived behavioral control were predictors for correct principles of MMH. There were significant differences between the mean scores of the theory constructs before and after the education in intervention group (P < 0.001); however, no significant differences were observed in the theory constructs in the control group after the intervention. Before the education, the mean score of MMH of the intervention group was 38.30 ± 6.45; but after, the education, this changed into 44.20 ± 6.01, and significantly increased (P < 0.001).

CONCLUSIONS

Educational intervention based on the TPB was effective in improving behavior for correct MMH in soldiers. Thus, the use of such educational programs according to the constructs of the planned behavior theory is recommended.

Physical risk factors identification based on body sensor network combined to videotaping

The aim of this study was to perform an ergonomic analysis of a material handling task by combining a subtask video analysis and a RULA computation, implemented continuously through a motion capture system combining inertial sensors and electrogoniometers. Five workers participated to the experiment. Seven inertial measurement units, placed on the worker's upper body (pelvis, thorax, head, arms, forearms), were implemented through a biomechanical model of the upper body to continuously provide trunk, neck, shoulder and elbow joint angles. Wrist joint angles were derived from electrogoniometers synchronized with the inertial measurement system. Worker's activity was simultaneously recorded using video. During post-processing, joint angles were used as inputs to a computationally implemented ergonomic evaluation based on the RULA method. Consequently a RULA score was calculated at each time step to characterize the risk of exposure of the upper body (right and left sides). Local risk scores were also computed to identify the anatomical origin of the exposure. Moreover, the video-recorded work activity was time-studied in order to classify and quantify all subtasks involved into the task. Results showed that mean RULA scores were at high risk for all participants (6 and 6.2 for right and left sides respectively). A temporal analysis demonstrated that workers spent most part of the work time at a RULA score of 7 (right: 49.19 ± 35.27%; left: 55.5 ± 29.69%). Mean local scores revealed that most exposed joints during the task were elbows, lower arms, wrists and hands. Elbows and lower arms were indeed at a high level of risk during the total time of a work cycle (100% for right and left sides). Wrist and hands were also exposed to a risky level for much of the period of work (right: 82.13 ± 7.46%; left: 77.85 ± 12.46%). Concerning the subtask analysis, subtasks called 'snow thrower', 'opening the vacuum sealer', 'cleaning' and 'storing' have been identified as the most awkward for right and left sides given mean RULA scores and percentages of time spent at risky levels. Results analysis permitted to suggest ergonomic recommendations for the redesign of the workstation. Contributions of the proposed innovative system dedicated to physical ergonomic assessment are further discussed.