Evaluation of Compressive and Shear Forces Exerted on the Lower Back in Manual Load Handling Tasks among Young Workers of Selected Block Maker Using 3DSSPP

Due to the negative influence of manual load handling on the lower back, it leads to low back disorders and high mechanical loads. The present study was aimed to investigate forces exerted on the lower back during manual handling in young workers in selected block-making workshops. This descriptive, cross-sectional study was carried out on 40 young workers with an average age of 31 years old in several block-making industries in 2020. 3DSSPP Software was used for biomechanical analysis of the forces exerted on the lower back. The prevalence of musculoskeletal disorders was assessed using the Standard Cornell Questionnaires. Spearman, Friedman, and ANOVA correlation tests via SPSS software version19 were used to determine the relationship between demographic variables, the prevalence of musculoskeletal disorders, the relationship between the prevalence of musculoskeletal disorders, the amount of compressive, and shear forces on workers backs. The results showed that the mean compressive and shear forces exerted to the lumbosacral joint (L5/S1) were 3194.85 ± 1064.326 and 473.17 ± 89.451 N, the intervertebral disc (L4/L5) were 3924.78 ± 4344.87 and 383.18 ± 154.554. The findings also indicated that the highest prevalence of pain was related to the lower back 45% and right knee 30%. There was a significant relationship between the mean score of musculoskeletal disorders obtained from the Cornell questionnaire with age, work experience, and weight and body mass (0.001 P). The shear forces exerted to the lower back were higher than the permissible levels by 30% to 37% of respondents, and on average 42.5% of them experienced compressive forces. Thus, it can cause a lot of injuries to the back if lasts for a long time. The results showed that manual load handling was dangerous for this group s ages. Consequently, people may suffer serious injuries and disorders particularly lower back disorders.