Ergonomic Solutions For Injuries Due To Repetitive Motion And Vibration
Ergonomics
The science of ergonomics studies and evaluates a full range of tasks and how they impact the health of the worker. Tasks evaluated include lifting, lowering, pushing, pulling, holding, and twisting. Back injuries are more likely to occur when an employee does any of these tasks while twisting.
Many ergonomic problems result from technological changes such as increased assembly line speeds, adding specialized tasks, and increased repetition; some problems arise from poorly designed job tasks. Any of these conditions can cause ergonomic hazards such as excessive vibration and noise, eye strain, repetitive motion, and heavy lifting problems. Improperly designed tools or work areas also can be ergonomic hazards.
Repetitive Motion
Repetitive motions or repeated shocks over prolonged periods of time as in jobs involving sorting, assembling, and data entry can often cause irritation and inflammation of the tendon sheath of the hands and arms, a condition known as carpal tunnel syndrome.
Repetitiveness is influenced by machine or line pacing, piece work, and unrealistic deadlines. For instance, an experienced worker packing apples (piece work) may complete many more similar exertions or movements than a new worker. Unfortunately, he or she may be performing at such a rapid rate that they may injure themselves over time. However, repetition alone is not an accurate predictor of injury. Other factors like force, posture, duration, and recovery time must also be considered.
Vibration
Various kinds of tools may cause vibration that could lead to “white finger” or hand-arm vibration syndrome (HAVS). This is especially dangerous when proper damping techniques are not applied if machines are not maintained, if tools are not alternated, or if a worker uses a vibrating tool for consecutive hours during a workday. Workers need to be trained on the hazards of working with vibrating tools, and should always allow the tool or machine to do the work.
Controls to help reduce vibration hazards include vibration isolators or damping techniques on equipment, isolating machine vibrations from the work surface, and the use of dampening material. Also, make sure rotating shafts are balanced, restrict the duration of exposure, and train workers on the hazards of vibrating parts.
Avoiding Hazards
Ergonomic hazards are avoided primarily by the effective design of a job or job site and better-designed tools or equipment that meet workers’ needs in terms of the physical environment and job tasks. Through thorough worksite analyses, employers can set up procedures to correct or control ergonomic hazards by:
- Using the appropriate engineering controls (e.g., designing or re-designing work stations, lighting, tools, and equipment);
- Teaching correct work practices (e.g., proper lifting methods);
- Employing proper administrative controls (e.g., shifting workers among several different tasks, reducing production demand, and increasing rest breaks); and,
- If necessary, providing and mandating personal protective equipment. Evaluating working conditions from an ergonomics standpoint involves looking at the total physiological and psychological demands of the job on the worker.
Overall, industrial hygienists point out that the benefits of a well-designed, ergonomic work environment can include increased efficiency, fewer accidents, lower operating costs, and more effective use of personnel.
