Workers who spread, level, and smooth concrete, mortar, or terrazzo mixtures may face hazards from stooped postures.
Prolonged bending of the back during the spreading, leveling and smoothing of concrete, mortar or terrazzo mixtures can cause injury to muscles, nerves, discs and ligaments of the low back. Non-specific low back pain is not the result of a fall or some other acute traumatic injury, so it can be difficult to identify a specific event that led to the injury. Continuous work in a 'stooped position' can lead to low back muscle strain, ligament sprain, a bulging or herniated disc, or other back problems.
Work loads or activities are of such a magnitude and character that a significant number of workers risk developing an MSD in the short or long term.
The 'stooped' position, characterized by prolonged periods of forward bending of the back, is considered one type of awkward back posture that is a risk factor for low back pain (LBP). Several scientific studies have found that stooped postures may cause low back pain compared to work that does not require stooping. Furthermore, it appears that the risk for LBP increases when more time is spent in the awkward postures or if forward bending is more pronounced. Biomechanics research shows that forces within the lumbar spine are higher when the lumbar spine is bent forward fully. In these postures, the spine is weaker and is supported by the ligaments instead of the back muscles. Research has shown that reliance on ligaments instead of muscles may increase the risk for LBP.
Stooped postures are common in construction work. In 2002, over 29% of lost work days in the construction industry were due to back injuries. Studies also show that back pain is common among construction workers, with over 50% of workers reporting low back pain in a year. In 1996, the University of Iowa surveyed 2,929 workers representing 13 different construction trades and found that 70% of workers experienced low back pain in the previous 12 months.
There has not been specific research on the development of back disorders among structural steel workers due to work in stooped postures. However, the evidence cited above on stooped posture as a risk factor, and high rates of back disorders in the construction industry, show that there is an increased risk of LBP among any structural steel workers who often works in stooped postures.
To assess exposure to stooped postures, determine how many hours per day the worker spends in with their back bent forward >30°, bent forward >45°, or twisted >30°. Also, visit Thomas Bernard's website for a host of practical ergonomic tools.
To assess the exposure to stooped postures, it is necessary to observe a worker drilling, grinding and sawing materials. Look for:
The risk of injury increases with more time spent in a bent forward posture and a greater degree of forward bending. General guidelines include:
Quantitative methods of measuring back posture are available (e.g. Lumbar Motion Monitor) but require technical expertise.Thomas Bernard's website has a host of practical ergonomics tools, including the Washington Department of Labor and Industries Checklist and the Rodgers Muscle Fatigue Assessment.
Thomas Bernard's website has a host of practical ergonomics tools, including three Microsoft Excel® based analysis tools based on the Liberty Mutual Manual Material Handling Tables.
Forceful and repetitive hand and wrist activities, and extreme hand/wrist postures, may cause hand, wrist, and elbow musculoskeletal disorders, including tendonitis. Numerous publications based on field studies among industrial workers in manufacturing and meatpacking have confirmed these risks. A combination of risk factors, such as forceful and repetitive hand activities, is an even greater risk factor for musculoskeletal disorders.
Many construction workers frequently use forceful, repetitive, and extreme hand/wrist postures during the normal course of their work. In 2002, 24.4% of lost work days in the construction industry were due to upper extremity injuries or illnesses. Epidemiologic studies also show that hand and wrist injury prevalence among construction workers is high. In 1996, the University of Iowa surveyed 2,929 workers representing 13 different construction trades. The investigators found that 43% of workers experienced hand and wrist pain, and 25% experienced elbow pain, in the previous 12 months.
Federal OSHA Standards are enforced by the U.S. Department of Labor in 26 states. There are currently 22 states and jurisdictions operating complete State plans (covering both the private sector and state and local government employees) and 5 - Connecticut, Illinois, New Jersey, New York and the Virgin Islands - which cover public employees only. If you are working in one of those states or jurisdictions you should ensure that you are complying with their requirements.