Biomechanical aspects of work-related musculoskeletal disorders

This article provides a review of the biomechanics literature on the low back and upper extremities. Biomechanics is the study of forces acting on and generated within the body and of the effects of these forces on the tissues, fluids, or materials used for diagnosis, treatment, or research purposes. The discussion begins with an overview of basic concepts and methods. This is followed by the two literature reviews. The study selection criteria are presented at the beginning of each review. The two bodies of literature differ in maturity; the research on the low back is more substantial. The number of studies reviewed is 196 for the low back and 109 for the upper extremities. While there are certainly individual factors that put a person at risk for back pain, overall, this body of literature indicates that back pain can be related to excessive mechanical loading of the spine that can be expected in the workplace. The literature also indicates that appropriate reduction of work exposure can decrease the risk of low back disorder. Hence, it is clear, from a biomechanical perspective, that exposure to excessive amounts of physical loading can increase the risk of low back disorder. The literature also reveals that there are strong relationships between physical loads in the workplace and biomechanical loading, internal tolerances, and pain, impairment, and disability associated with the upper limb. Although many of these relationships are complex, the associations are clear. The biomechanical literature has identified relationships between physical work attributes and external loads for force, posture, vibration and temperature. Research has also demonstrated relationships between external loading and biomechanical loading (i.e. internal loads or physiologic responses). Relationships between external loading and internal tolerances (i.e. mechanical strain or fatigue) have also been demonstrated. Finally, relationships have been shown between external loading and upper limb pain, discomfort, impairment or disability. Although the relationships exist, the picture is far from complete. Individual studies have, for the most part, not fully considered the characteristic properties of physical work and external loading (i.e. magnitude, repetition or duration). Few studies have considered multiple physical stress factors or their interactions. The existence of these interactive relationships supports the load-tolerance model presented in this paper.

Keywords:

• Back
• Cumulative Trauma
• Elbow
• Fingers
• Hand
• Neck
• Shoulder
• Wrist
• Upper Limb