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

Manual load handling is a work activity related to low back disorders and can impose a high mechanical load on the lower back. The present study aimed to investigate forces exerted on the lower back during manual handling in young workers in selected block maker workshops. This Descriptive, cross-sectional study was carried out on 40 young workers with an average age of 31 years in several block maker industries in 2020. 3DSSPP Software was used for biomechanical analysis of the forces exerted on the lower back. Prevalence of musculoskeletal disorders was assessed using the Standard Cornell Questionnaires. To analyze the data from SPSS19 software and Spearman, Friedman and ANOVA correlation tests were used to determine the relationship between demographic variables and the prevalence of musculoskeletal disorders and the relationship between the prevalence of musculoskeletal disorders and 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 3194.8±1064.4 and 473.2± 89.5 N, respectively, and for the intervertebral disc (L4 / L5) were 3924.8±434.9 and 383.2 ±154.5, respectively The findings also indicated that the highest prevalence of pain was related to the lower back and right knee with 45% and 30%, respectively. The direct relationship exists 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 in about 30 to 37% of people and the compressive forces were on average in 42.5% of people, which can cause a lot of injuries to the back in the long term. The results obtained according to the study population show that manual load handling for these ages is dangerous and in the future and at older ages, people may suffer serious injuries and disorders, especially in the lower back.