<unk> s can arise from the interaction of physical factors with ergonomic, psychological, social, and occupational factors. Biomechanical<unk> s 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<unk> s 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.<unk>  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. Individual differences People vary in their tendency to get<unk> s. Gender is a factor, with women having a higher incidence of<unk> s than men. Obesity is also a factor, with overweight individuals having a higher risk of some<unk> s, specifically of the lower back. Psychosocial There is a growing consensus that psychosocial factors are another cause of some<unk> s. Some theories for this causal relationship found by many researchers include increased muscle tension, increased blood and fluid pressure, reduction of growth functions, pain sensitivity reduction, pupil dilation, body remaining at heightened state of sensitivity. Although there is no consensus at this time, some of the workplace stressors found to be associated with<unk> s in the workplace include high job demands, low social support, and overall job strain. Researchers have consistently identified causal relationships between job dissatisfaction and<unk> s. For example, improving job satisfaction can reduce 17-69 per cent of work-related back disorders and improving job control can reduce 37-84 per cent of work-related wrist disorders. Occupational Because workers maintain the same posture over long work days and often several years, even natural postures like standing can lead to<unk> s like low back pain. Postures which are less natural, such as twisting of or tension in the upper body, are typically contributors to the development of<unk> s due to the unnatural biomechanical load of these postures. There is evidence that posture contributes to<unk> s of the neck, shoulder, and back. Repeated motion is another risk factor for<unk> s of occupational origin because workers can perform the same movements repeatedly over long periods of time (e.g. typing leading to carpal tunnel syndrome, lifting heavy objects leading to herniated discs/slipped discs), which can wear on the joints and muscles involved in the motion in question. Workers doing repetitive motions at a high pace of work with little recovery time and workers with little to no control over the timing of motions (e.g. workers on assembly lines) are also prone to<unk> s due to the motion of their work. Force needed to perform actions on the job can also be associated with higher<unk>  risk in workers, because movements which require more force can fatigue muscles quicker which can lead to injury and/or pain. Additionally, exposure to vibration (experienced by truck drivers or construction workers, for example) and extreme hot or cold temperatures can affect a worker's ability to judge force and strength, which can lead to development of<unk> s. Vibration exposure is also associated with hand-arm vibration syndrome, which has symptoms of lack of blood circulation to the fingers, nerve compression, tingling, and/or numbness. Recent epidemiological studies identify gender as a significant risk factor in occurrence of<unk> s among workers in gender-related occupations, e.g. hairdressers.
Musculoskeletal disorder
Spinal disease
Central nervous system disease
Neurological disorder
Bone disease
Musculoskeletal injury
Brain damage
Pigmentation disorder