substantial evidence that psychosocial factors, in addition to the physical factors cited above (see response to Question 4), are significant contributors to musculoskeletal disorders. Relevant factors are repetitive, boring jobs, a high degree of perceived psychosocial stress, and suboptimal relationships between worker and supervisor.
The weight and pattern of both the scientific evidence and the very practical quality improvement data support the conclusion that primary and secondary prevention interventions to reduce the incidence, severity, and consequences of musculoskeletal injuries in the workplace are effective when properly implemented. The evidence suggests that the most effective strategies involve a combined approach that takes into account the complex interplay between physical stressors and the policies and procedures of industries.
The complexity of musculoskeletal disorders in the workplace requires a variety of strategies that may involve the worker, the workforce, and management. These strategies fall within the categories of engineering controls, administrative controls, and worker-focused modifiers. The literature shows that no single strategy is or will be effective for all types of industry; interventions are best tailored to the individual situation. However, there are some program elements that consistently recur in successful programs:
1. Interventions must mediate physical stressors, largely through the application of ergonomic principles.
2. Employee involvement is essential to successful implementation.
3. Employer commitment, demonstrated by an integrated program and supported by best practices review, is important for success.
Although generic guidelines have been developed and successfully applied in intervention programs, no single specific design, restriction, or practice for universal application is supported by the existing scientific literature. Because of limitations in the scientific literature, a comprehensive and systematic research program is needed to further clarify and distinguish the features that make interventions effective for specific musculoskeletal disorders.
Occupations that involve repetitive lifting, e.g., warehouse work, construction, and pipe fitting, particularly when that activity involves twisting postures, are associated with an increased risk for the complaint of low back pain and, in a few studies, an increased risk for lumbar disc herniation.