What Are The Principles Of Ergonomics?

8 Fundamental Ergonomic Principles for Better Work Performance

Principle 1. Maintain Neutral Posture

Neutral postures are positions in which the body is relaxed and balanced while sitting or standing, putting minimum tension on the body and keeping joints aligned. 

Neutral postures reduce the stress on the muscles, tendons, nerves and bones and allow maximum control and output of force.

The opposite of a neutral posture is an “awkward posture.” Awkward postures move in range of motion away from the neutral posture towards the extremes. It places more stress on the worker’s musculoskeletal system, is and should be avoided as a potential risk factor for Musculoskeletal Disorders (MSDs).

Principle 2. Work in the Power / Comfort Zone

The lifting power zone is near the body, between the height of the mi-thigh and mid-chest. This zone is where the arms and back are most able to lift with the least effort.

This can also be called the “hand shake zone” or “comfort zone.” The idea here is to eliminate unnecessary reach and maintain a supportive stance, if you can “shake hands with your work.”

Working from the power / comfort / handshake zone ensures you work from proper heights and reaches, reducing risk factors for MSD and enabling more efficient and pain-free work.

Principle 3. Allow for Movement and Stretching

The musculoskeletal system is often referred to as the system of movement of the human body, and is intended for movement.

Sitting in a static position for long periods of time can induce tiredness in your body. This is known as static charging.

Stretching reduces fatigue, improves muscle balance and posture, and improves coordination of the muscles. Everyone in life is an athlete so you need to prepare your body for work by warming up to improve performance and lower risk of injury. A warm-up stretching exercise is a great way to get your body ready to work.

Taking frequent stretch breaks over the course of your work day is also helpful to get your blood moving and regain strength.

Principle 4. Reduce Excessive Force

Excessive force is one of the chief risk factors for ergonomics. Many tasks at work require high loads of force on the human body. In response to high force requirements, muscle effort increases which increases fatigue and risk of an MSD.

There are various factors that impact force, but the aim is to identify when unnecessary force is required in a job or activity and then find ways to reduce that force.

Eliminating the requirements for excessive force will reduce worker fatigue and the risk of developing MSD in most workers. The use of mechanical aids, counterbalance systems, height adjustable lifting tables and workstations, powered equipment and ergonomic tools will reduce work effort and muscle exertion.

Principle 5. Reduce Excessive Motions

Repetitive motion is yet another of the primary risk factors for ergonomics. Most job activities and cycles are repetitive in nature, and are often regulated by expectations of hourly or daily output and work processes. High repetition of tasks may lead to the development of MSD when combined with other risk factors including high force and/or uncomfortable postures. If the work time is 30 seconds or less then a task is considered highly repetitive.

There should be a decrease in repetitive or needless movements where possible. It is necessary to avoid excessive force requirements and uncomfortable postures in conditions where that is not possible.

Other control methods to consider are Job enlargement, job rotation and counteractive stretch breaks.

Principle 6. Minimize Contact Stress

Contact stress results from continuous contact or rubbing between hard or sharp objects / surfaces and sensitive body tissue, such as soft finger tissue, palms, thighs and feet, according to OSHA. This contact induces concentrated pressure for a small body area which may impair blood, nerve function, or tendon and muscle movement.

Examples of contact stress include resting wrists on the sharp edge of a desk or workstation while performing tasks, pressing tool handles into the palms, especially when they can not be put down, tasks requiring hammering by hand, and sitting without adequate knee space.

Principle 7. Reduce Excessive Vibration

Multiple studies have shown that regular and frequent vibration exposure can result in permanent adverse health effects which are most likely to occur when contact with a vibrating tool or work process is a regular and significant part of a person’s job.

Hand-arm vibration can cause a range of conditions collectively known as hand-arm vibration syndrome (HAVS), as well as specific illnesses such as white finger or Raynaud’s syndrome, carpel tunnel syndrome, and tendinitis. Vibration syndrome has detrimental neurological and circulatory effects on the fingertips. The signs and symptoms include numbness, pain and blanching (pale and ashen-turning).

Principle 8. Provide Adequate Lighting

Poor lighting in the workplace is a common problem which may affect the level of comfort and efficiency of a worker. Too much or too little light complicates work-just imagine trying to do your job without sight!

The provision of adjustable job lighting to staff is often an easy solution to problems with lighting. Take steps to control screen glare at a computer workstation, and make sure the monitor is not placed in front of a window or a bright background.