Background & objective: The present study was conducted to examine the risk factors associated with hand activity and to determine their cumulative effect on the development of upper extremity musculoskeletal disorders.

Methods: The present clinical trial was conducted on 24 men and 6 women employed at a tea factory in Fuman in northern Iran. The human body map was used to assess the prevalence of musculoskeletal disorders and the HAL-TLV method was used for determining the risk levels. All the tests were analyzed at a significance level below 0.05. The Wilcoxon test was used to measure the likelihood of developing musculoskeletal disorders. The Kappa test was used to compare changes occurring in the HAL-TLV results before and after the intervention. The data obtained were then analyzed in SPSS-16.

Results: The results obtained through the HAL-TLV method showed that, for the right hand, 7 participants were at a risk level below 0.56 (the safe zone), 10 at the risk level between 0.56 and 0.78 (the caution zone) and 13 at the risk level above 0.78 (the danger zone) before the intervention however, after the intervention, 27 participants fell at the safe zone, 2 at the caution zone and only 1 at the danger zone. The results obtained for the left hand showed that, before the intervention, 5 workers were at the safe zone, 12 at the caution zone and 13 at the danger zone after the intervention, however, 28 workers were at the safe zone, 1 at the caution zone and only 1 at the danger zone.

Conclusion: The assessment of the risk factors associated with job-related musculoskeletal disorders and the design and implementation of technical, administrative and educational interventions can help reduce the prevalence of these disorders.