Recent studies indicate potential links among work organization, job stress, and work-related musculoskeletal disorders (WRMDs). In this paper we propose several pathways for a theoretical relationship between job stress and WRMDs. These pathways highlight the physiological, psychological, and behavioral reactions to stress that can affect WRMDs directly and indirectly. One model stipulates that psychosocial work factors (e.g., work pressure, lack of control), which can cause stress, might also influence or be related to ergonomic factors such as force, repetition, and posture that have been identified as risk factors for WRMDs. In order to fully understand the etiology of WRMDs, it is important to examine both physical ergonomic and psychosocial work factors simultaneously. Smith and Carayon-Sainfort (1989) have proposed a model of the work system for stress management that provides a useful framework for conceptualizing the work-related factors that contribute to WRMDs. Practical applications of this resear ch include practitioners taking into account psychosocial work factors and job stress in their efforts to reduce and control WRMDs.
There has recently been interest in the role of occupational stress in the causation and aggravation of upper-extremity work-related musculoskeletal disorders (WRMDs; Moon, 1993; Moon & Sauter, 1996). Some believe that stress is the primary cause of the symptomology associated with many upper-extremity WRMDs (Hadler, 1990; Hadler, 1992). However, others, such as Smith (1984), Smith and Carayon (1996), and LeGrande (1993), believe that work organization and psychosocial factors at the workplace that might lead to psychological stress are important WRMD risks but do not preclude traditional ergonomic risk factors such as repetition, force, and posture.
Different terms have been used to describe WRMDs, such as cumulative trauma disorders, repetitive strain injuries, overuse injuries, and repetitive motion injuries. Putz-Anderson (1988) defined cumulative trauma disorders as a collection of health problems that have three characteristics. First, they are cumulative; that is, injuries develop over a long time as a result of repeated, continuous exposure of a particular body part to stressors. Second, the repeated, continuous exposure to stressors leads to trauma of tissues and joints. Third, WRMDs are physical ailments or abnormal conditions.
Putz-Anderson (1988) identified three types of upper-extremity WRMDs: tendon disorders (e.g., tendinitis), nerve disorders (e.g., carpal tunnel syndrome), and neurovascular disorders (e.g., thoracic outlet syndrome). The psychosocial and stress considerations in lower back pain have been examined by Feyer, Williamson, Mandiyk, DeSilva, and Healy (1992) and Bigos et al. (1991).
This paper focuses on disorders of the upper extremities (i.e., in the neck, shoulders, arms, and hands), which have not been examined in detail in relation to work organization and psychological stress.
Upper-extremity WRMDs have become more prevalent in the American workforce during the 1990s (Bureau of Labor Statistics [BLS], 1994). Recent interest by the Occupational Safety and Health Administration (OSHA) in the red meat packing industries (OSHA, 1990) and the increase in hand, wrist, shoulder, and neck problems accompanying the widespread use of computer-based technology (Gerr, Letz, & Landrigan, 1991) have highlighted this increase in upper-extremity WRMDs. Although occupational lower back injuries have been a substantial problem for decades, the magnitude of upper-extremity WRMDs has not been prominent until the last decade. Work-related musculoskeletal disorders are an increasing concern to occupational health and safety professionals, ergonomists, industrial engineers, employers, unions, and workers. The BLS has shown that all types of WRMDs have increased as a percentage of total occupational illnesses. …