Journal of Ergonomics

Introduction: Manual load lifting is the most common and most stressful activity in manual handling of loads that imposes the highest possible amount of biomechanical pressure on the body, particularly on the spine. The present study was conducted to determine the prevalence of musculoskeletal disorders and to estimate the mechanical force exerted on the lower back in workers responsible for manual load lifting.

Material and Methods: The present cross-sectional study was conducted on 120 workers responsible for manual load lifting activities in 7 industrial settings in the city of Shiraz. The Nordic Musculoskeletal Questionnaire (NMQ) was used for determining the prevalence of musculoskeletal disorders and the 3DSSPP software was used to estimate the forces exerted on the lower back during load lifting. Data were then analyzed in SPSS-19.Findings: The results showed that lower back problems constitute the most prevalent musculoskeletal disorder (68.3%). Evaluations conducted in 3DSSPP showed that in 17.5% of the cases, compressive forces, and in 10.8% of the cases, shearing forces exerted on the L5-S1 disc were higher in the workers than the permissible levels. There were no significant differences between the rate of the prevalence of lower back pain at different levels of compressive and shearing forces exerted on the disc (p>0/05).

Results: This finding might indicate the limitations of the method used in this study for conducting a comprehensive assessment of loads exerted on the spine.

Conclusion: The prevalence of musculoskeletal disorders, in particular lower back pain, was estimated to be high among the subjects studied. The risk levels of compressive and shearing forces exceeded the permissible amount in a low percentage of the workers studied. The 3DSSPP software might have certain limitations in the assessment of the pressure exerted on the spine.

Introduction: In the recent decades, owing to the advancement of technology, most jobs and occupations require the use of computers. Lack of information about ergonomic conditions has resulted in various occupational injuries. Break time between work and doing exercise, help in reduction of musculoskeletal symptoms. The present study aimed to use a new ergo-feedback software and to assess its usability in office staff.

Methods: Thirty office staff participated in this study. In the first step, muscle-skeletal symptoms were checked by a body map checklist. Then, the Borg score was determined by the participants, initially and after one work day. The software was then run in their systems and they worked with it for about two weeks. After two weeks, the Borg scale was completed again and efficacy of the software was evaluated by the system usability scale (SUS). Data analysis was performed using descriptive statistics (mean and standard deviation) and Wilcoxon test. Statistical analysis was done by the SPSS software version 19.

Results: The results showed that there was a significant difference between the Borg score pre and post intervention (P > .05). The majority of the users were satisfied with the software with the SUS score showing about 82.25% satisfaction.

Conclusions: According to this study, office workers were satisfied with using this software and it can help reduce musculoskeletal symptoms during a prolonged time period.