Personal or Individual Risk Factors

There are certain factors inherent in work tasks that can increase our risk for the onset of musculoskeletal injuries (MSI), such as:

• fixed and constrained postures that are frequently awkward, uncomfortable and maintained for too long a time,
• repetitious and forceful hand movements, and
• a high pace of work.

These factors are discussed in greater detail in our companion OSH Answers document Office Ergonomics - Major Work-Related Factors.

Other factors of a strictly personal nature also contribute to our risk for MSI. These include our state of health or fitness, our life style, our posture, and our work habits. These factors are the focus of this document.

State of health

Although the evidence is not conclusive, there is general agreement among researchers that individuals with medical conditions are more likely to have musculoskeletal injuries. Examples of these conditions include hyper-mobile joints, arthritis, diabetes, or thyroid disease.

Fitness

Poor physical fitness, and obesity make us more susceptible to musculoskeletal injuries. For example, poor fitness is a prime cause of weariness and fatigue which are also commonly recognized to be factors that can contribute to the onset of MSI. So, although there is no direct relation between poor fitness and muscular discomfort and eventual injury, we can regard a lack of fitness as a strong risk factor for injury, and any feeling of fatigue as a warning signal.

The body positions held while typing and individual typing styles are so significant in the cause of repetitive motion injuries (RMI) that their impact cannot be overemphasized. Some experts consider that they outweigh any other factors.

Slouching while sitting with the back slumped against the backrest of the chair compresses the spine and can lead to low back pain. It also puts the head in an imbalanced position, contributing to neck and shoulder problems. Additionally, a slouchy, sitting position encourages the worker to rest the wrists on the edge of the desk in the dorsiflex position (i.e., hands bent upwards or backwards at the wrist). This is one of the most important MUST NOT DOs in RMI prevention.

There are many poor typing techniques, even among trained and highly skilled typists. Pounding the keys harder than necessary can cause tingling in the fingertips and pain in the finger joints. Pressing the keys rather than lightly touching them strains the tendons of the fingers, hands and forearms. Pecking at the keys instead of touching them lightly usually requires one to lift the remaining fingers and thumb. Over time, these repetitive movements can lead to forearm tendonitis and de Quervain's disease.

Any typing posture with arms unnecessarily away from the body puts a lot of strain on shoulders and neck makes typing more strenuous (forceful) than need to be. Examples are typing with arms extended forwards or to the sides or with shrugged shoulders.

In addition to the repetitive nature of typing, the force used is another risk factor contributing to the occurrence of RMIs: the greater the effort the higher the risk for RMIs.