Musculoskeletal disorders (MSDs) are injuries or pain in the human musculoskeletal system, including the joints, ligaments, muscles, nerves, tendons, and structures that support limbs, neck and back. MSDs can arise from a sudden exertion (e.g., lifting a heavy object), or they can arise from making the same motions repeatedly repetitive strain, or from repeated exposure to force, vibration, or awkward posture. Injuries and pain in the musculoskeletal system caused by acute traumatic events like a car accident or fall are not considered musculoskeletal disorders. MSDs can affect many different parts of the body including upper and lower back, neck, shoulders and extremities (arms, legs, feet, and hands). Examples of MSDs include carpal tunnel syndrome, epicondylitis, tendinitis, back pain, tension neck syndrome, and hand-arm vibration syndrome.
MSDs can arise from the interaction of physical factors with ergonomic, psychological, social, and occupational factors.
MSDs are caused by biomechanical load which is the force that must be applied to do tasks, the duration of the force applied, and the frequency with which tasks are performed. Activities involving heavy loads can result in acute injury, but most occupation-related MSDs are from motions that are repetitive, or from maintaining a static position. Even activities that do not require a lot of force can result in muscle damage if the activity is repeated often enough at short intervals. MSD risk factors involve doing tasks with heavy force, repetition, or maintaining a nonneutral posture. Of particular concern is the combination of heavy load with repetition. Although poor posture is often blamed for lower back pain, a systematic review of the literature failed to find a consistent connection.
People vary in their tendency to get MSDs. Gender is a factor, with women having a higher incidence of MSDs than men. Obesity is also a factor, with overweight individuals having a higher risk of some MSDs, specifically of the lower back.