Office Chair, Posture, and Driving Ergonomics

Proper standing posture
Figure 1: Proper standing posture
(larger view)

Proper support for concrete floors
Figure 2: Proper support for concrete floors
(larger view)

Good sitting posture
Figure 3: Good sitting posture
(larger view)

Good driving posture
Figure 4: Good driving posture
(larger view)

Posture is very important both at home and on the job. Back-friendly posture is a valuable component of preventing or managing back pain while performing any activity. Incorrect posture while standing for long periods of time, sitting in an office chair, and driving are all common causes of back pain.

Standing Posture

Maintaining the natural curve of the spine when standing promotes "good posture". So what does that mean? The human spine looks a little bit like an S from the side, and maintaining those two curves is important (see Figure 1).

  • Keep your head directly over the shoulders (i.e. "chest out, head back")
  • Keep the shoulders directly over the pelvis
  • Tighten the core abdominal muscles
  • Tuck in the buttocks
  • Place the feet slightly apart, with one foot positioned slightly in front of the other and knees bent just a little bit (i.e., not locked).
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If this posture is new it may feel strange at first, but after awhile it will feel natural. If it feels too weak or tiring, use light weights or elastic bands to work the muscles between the shoulder blades (e.g. rhomboids and middle trapezius). It will quickly get easier.

If standing on a concrete floor is required at work, it is best to wear shoes with good support and cushioning. A rubber mat placed on the concrete floor will ease pressure on the back and enhance the favorable ergonomic conditions. Use a railing or box to prop one foot up while standing to help take pressure off the back. This standing position takes some practice. Remember to change feet and positions every 20 minutes (see Figure 2).

Office Chair Sitting Posture

Posture is important for sitting in office chairs and at a workstation. Many of us spend hours in front of the computer, resulting in back pain or neck pain. Much of this pain may be avoided by a combination of:

  • Adopting a user-friendly workstation by adjusting the office chair, computer and desk positioning
  • Modifying sitting posture in an office chair. Many people sit towards the front of their chair and end up hunching forward to look at their computer screen. The better seated posture is to sit back in the office chair and utilize the chair's lumbar support to keep the head and neck erect.
  • Taking stretch breaks and walking breaks if sitting in an office chair for long periods of time.

A consistent, comfortable workstation depends on where the computer screen is situated, where the hands and feet are placed, and the kind of office chair.

Figure 3 provides a common sense, easily remembered approach to fitting a seated workstation to the individual worker. To make it work, begin by selecting or adjusting the position or the work surface, then adjust the office chair.

  • Choose the surface height for the desk (standing, sitting or semi-seated) best for the task to be performed. Architects and draftsman may want a higher surface for drawing while computer entry work could be seated or standing, depending on the need to use other tools or references. The specific height of the work surface will also need to vary based on the height of the individual worker.
  • Adjust the seat of the office chair so that the work surface is "elbow high." A fist should be able to pass easily behind the calf and in front of the seat edge to keep the back of the legs from being pressed too hard and the feet from swelling. Two fingers should slip easily under each thigh. If not, use a couple of telephone books or a footrest to raise the knees level with the hips. The backrest of the office chair should push the low back forward slightly. If these adjustments cannot be adequately made with the existing office chair, a different make or type of chair may be considered.
  • Fit the height of the computer screen. Sit comfortably in the newly adjusted office chair. Close both eyes and relax. Then, slowly reopen them. Where the gaze initially focuses should be when the eyes open is the place to put the center of the computer screen. The screen can be raised using books or a stand if needed.

Driving Posture To and From Work

Regardless of travel time to and from work, one's seated posture while driving can either contribute to or alleviate back discomfort. Similar to those that sit in an office chair for hours, those with extensive commutes (an hour or more each way) can have an adverse impact on their back.

First and foremost, it is important to sit with the knees level with the hips. Either a rolled up towel or a commercial back support placed between the lower back and the back of the seat for more comfort and support of the natural inward curve of the low back.

Drivers are advised to sit at a comfortable distance from the steering wheel. Reaching increases the pressure on the lumbar spine and can stress the neck, shoulder, and wrist, so sitting too far away can aggravate back pain (see Figure 4). However, sitting too close can increase risk of injury from the car's airbag. According to the National Highway Traffic Safety Administration, drivers (and front-seat passengers) should buckle their seat belts and keep about 10 inches between the center of the air bag cover and their breastbone to reduce the risk of air bag injury yet still be protected by the air bag in the event of a collision.

Good posture combined with body mechanics (the way activities are performed throughout the day can substantially improve the way one's back and neck feels at the end of the workday.

References

  • U.S. Department of Transportation, NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION. “Air bags and on-off switches”, www.safercar.gov, accessed 9/14/06.
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