This study determined the influence of short term exposure to mechanical factors on regional musculoskeletal pain on full time newly employed workers (1081 subjects (median age 23, range 20-27) from 12 occupational groups and information collected by questionnaire.
Subjects indicated on a blank body manikin any low back, shoulder, wrist or forearm or both, or knee pain which had occurred during the past month and had lasted more than 1 day.Several specific manual handling activities were found to be associated with low back, shoulder, and knee pain. Carrying weights of more than 50 lbs (23 kg) on one shoulder was the factor which was most strongly associated with low back pain, shoulder pain, and knee pain , whereas forearm pain was most strongly associated with repetitive movements of the wrists.
By contrast very few postures were associated with regional pain, although bending forwards in an uncomfortable position for at least 15 minutes was associated with shoulder pain and kneeling for at least 15 minutes was associated with knee pain. Exposure to mechanical factors was most strongly associated with pain at multiple sites rather than with pains in individual regions. The conclusion was that even workers with only short term exposure to mechanical factors, musculoskeletal pain is increased. (Nahit ES, Macfarlane GJ, Pritchard CM, Cherry NM, Silman AJ: Short term influence of mechanical factors on regional musculoskeletal pain: a study of new workers from 12 occupational groups.Occupational & Environmental Medicine. 58(6):374-81, 2001).
In this next study, the incidence of occupational injuries was related to several demographic factors, including low family income and rural residence, and several job characteristics, including working in a high-hazard occupation, job dissatisfaction, and exposure to six specific hazardous job activities: (1) performing lots of physical effort on the job, (2) lifting or carrying more than 10 lbs, (3) using stairs and inclines, (4) kneeling or crouching, (5) reaching, and (6) hearing special sounds.
These results suggest targeted prevention strategies for decreasing the incidence of work-related injuries and illnesses, such as worker self-assessment of the total physical effort demanded by a job and periodic monitoring of workforce job satisfaction. (Dembe AE, Erickson JB, Delbos R: Predictors of work-related injuries and illnesses: national survey findings. Journal of Occupational & Environmental Hygiene. 1(8):542-50, 2004).