Human Factors and Ergonomics (HF&E) is a multidisciplinary field incorporating contributions from psychology, engineering, industrial design, graphic design, statistics, operations research and anthropometry. In essence it is the study of designing equipment and devices that fit the human body and its cognitive abilities. The two terms “human factors” and “ergonomics” are essentially synonymous.
HF&E is employed to fulfil the goals of health & safety and productivity. It is relevant in the design of such things as safe furniture and user-friendly machine and equipment interfaces. Proper ergonomic design is necessary to prevent repetitive strain injuries (RSIs) or associated musculo-skeletal disorders, which can develop over time and can lead to long-term disability.
Central to the design of good ergonomic seating is the ability to adjust the back support and seat angle of the chair so as to tilt the user’s pelvis and allow the spine to adopt a natural “S-shaped” lordotic curve, allowing the body weight to be borne by the skeletal structure rather than the muscles.
Obtaining benefit from current Seating Ergonomics primarily means three things:
1. that the office chair fits the user and has appropriate adjustability options.
2. that the office chair enables and stimulates a variety of sitting positions.
3. that the office chair is user- friendly towards a cognitive understanding of the use of the functional controls that might allow for repeated use.
Continuous periods of sitting in an incorrectly supported position can result in degeneration of the spinal cartilage (discs) situated between the vertebrae. Lumbar area support has been the traditional method of promoting a lordotic posture.
Avoid problems that may arise from sitting incorrectly:
1. Head – Your head weighs as much as a bowling ball – unsupported it can lead to strains in your neck. Poor blood flow also leads to poor concentration. Create a supportive posture and consider additional support.
2. Organs – Poor posture restricts the function of your organs from stomach digestion to lung functions. Improve posture through better seat mechanics and enforcing a lordotic (S-shaped) spinal curve.
3. Back – Poor posture (kyphotic back shape) leads to disc pressure, constricted blood flow and excessive strain on your back resulting in weakening and fatigue. Ensure that the vertebrae line up as if standing by assuming a good posture with correct support for the lumbar area.
4. Arms – Unsupported arms can use up to 80% more effort leading to tendinitis in the wrist, strain in the shoulders, and upper back problems. Adjustable armrests provide support.
5. Legs – 80% of your weight when seated goes through your ischial tuberocities and one of your largest veins runs at the back on the knee. Constricted blood flow creates fatigue. Ensure that the seat pad is of suitable dimensions.