assessment of manual material lifting and comparison of oral and booklet training intervention for improvement of working conditions in a porcelain production industry: a randomized controlled trial

background: proper training on how to correctly handle loads is one key point for prevention of low back disorders. this study was conducted with the objectives of assessing manual material lifting activities and comparing two methods of training intervention in a porcelain company.   methods: in this randomized controlled trial which was conducted in a porcelain company, all male employees with lifting activities (n=204) participated. the data were collected using nordic musculoskeletal disorders questionnaire and lift/ lower force risk assessment software for assessing manual material lifting. intervention methods included booklet and oral training. data were analyzed using mann-whitney u and chisquare tests using spss software (version 17.0).   results: the most prevalent musculoskeletal disorders symptoms were reported in the knee (52.5%), feet (45.1%), and lower back (43.6%). risk assessment before intervention showed that in 62.7% of the workers studied, the level of exposure to musculoskeletal risks was in action level (al) 1, 31.9% in al 2 and 5.4% in al 3. the risk assessment after intervention showed that in 77.5% of the workers studied, the level of exposure to musculoskeletal risks was in action level (al) 1, 20.6% in al 2 and 2% in al 3 (p<0.001). also, statistical analysis revealed that oral training (24.5%) was more effective than the booklet training (11.8%) (p=0.018).   conclusion: this study showed that training intervention could be effective in correction of methods of manual material lifting of workers. it seems oral training for workers of porcelain industry is more effective than the booklet training.   trial registration number: irct2015050322071n1.