Ergonomic Worksite Adjustment Sequence

We are not physicians. The following recommendations for work site adjustment are a result of many years working with people with varying degrees physical health, injury or limitations. If you experience pain or discomfort you should immediately contact your doctor for specific posture support advice and discontinue this adjustment sequence.

Seat and Back Adjustment

1. Seat Height
Using the floor as a basis for all adjustments to the chair begin with setting the height of the seat. Seat height should be set so that the workers thigh has a very slight downward angle from the hip to the knee.

2. Seat Pitch
The pitch of the seat should be set so that the worker feels support evenly all along the back of their legs from the buttock to the back of the thigh.

3. Back Height
Nearly all chairs have some lumbar support. The height of the back should be adjusted so as to apply the lumbar support curve to the corresponding lumbar curve of the worker. Be careful not to allow the lumbar support to be applied too low. If the chair back is positioned too low it may cause a forward rotation of the pelvis. The sensation the user feels is similar to excessive lumbar support. Try moving the back up and down to insure there is proper mating of the lumbar support and the user's lumbar curve.

4. Back Pitch
This adjustment is similar to the seat adjustment. The pitch should be adjusted to insure even support up and down the back with support being applied to the largest portion of the back while in a working posture. The pivot point of the back pitch adjustment is behind the seat. When the support is greater at the lumbar the chair back pitch should be moved toward the user to balance the support.

Arm Support Adjustment

1. Arm Supports
Arms should be adjusted laterally to a point where support is provided evenly with the arms comfortably positioned close to the torso. Once the lateral adjustment is complete move the height of the support to a position where the shoulder is supported comfortably. The height of the arm support should not interfere with the workers ability to move their hands about the work surface. Proper arm support height allows the workers arms to float just above the arm support while tasking with minimal contact with the arm supports.

2. Workstation
Once the chair adjustment is complete it is time to move onto the rest of the workstation. If possible set the work surface at ¼" above the height of the arm supports on the chair. Remember to make your measurement while the worker is seated in the chair. Sometimes the work surface height can not be effected. In those cases it may be necessary to now change the height of the chair. Most of the time in these situations the chair will need to be raised. You will then need to raise the floor. We should say raise the basis of your adjustments. You can do this with a foot support of some kind. Anything that will support the workers feet at an equal distance from the floor to that of the height change to the chair. When adjusting the chair upward to meet the work surface height measure the amount of change then add a foot support with elevation equal to that measurement. Keep everything in as close as to the worker as possible. Next set the height of the monitor. There are a couple of theories regarding proper monitor height. At ERGOdynamics we believe the monitor should be set at an elevation where the top of the monitor is on a level plane with the workers eyebrows. This puts the primary viewing and working area within a 10-15 degree angle from the visual horizon when the head is held in a neutral posture.

Monitor Height Adjustment

Another technique developed at ERGOdynamics for setting monitor height requires an understanding of the software used most by the worker. DO NOT USE THIS TECHNIQUE IF WORKER HAS NECK PAIN OR A PREVIOUS INJURY. Some software like Email programs require focus on about 1/3 of the screen area most of the time. Other software like spreadsheet programs utilize nearly the entire screen. The goal is to target the mid point of the area of the screen most used. To set the height of monitor using this technique first turn the monitor off. This is done to eliminate any distractions on the screen. Now have the worker sit in what is a normal working posture and distance from the monitor. Workers who wear bifocal or progressive lenses may have difficulty with a blank screen. A tape measure or ruler held vertical may be helpful. Next have them close their eyes and move their head slowly in a circular motion as though they are stretching neck muscles. Do this for 2 or 3 rotations. Now keeping their eyes closed have them stabilize their head in a neutral and comfortable posture. Wait 2 seconds and ask them to open their eyes, focus on the screen and immediately point to the area of the screen where their focus is drawn. Repeat this process 2 or 3 times keeping a mental note of the area of the screen selected. Do not put anything on the screen to indicate the points selected. When this process is complete you will have identified the primary focal point for this worker. Now move the monitor up or down so that this point is midway up and down for the area of the screen that is most used.