Desk-Fit 360 Part 1 – Take a seat.
The first of our 5-part series on ergonomics and posture will discuss sitting position.
We generally encounter 2 basic suboptimal sitting postures:
The majority of people tend to sit with rounded backs and there are a number of different reasons why this occurs. Firstly, many of us sit on the area between the Ischial tuberosities (“sit” bones) and the coccyx (“tail” bone). With females, this habit likely originates from childhood where young girls tend to sit on the toilet with their pelvis rocked back in order to wee in the bowl. In men, the posture is more likely to do with tightness in the structures at the back of the hip, a lack of motor control, as well as a certain degree of laziness. Either way, sitting on this area of the pelvis puts the lower back in a rounded position (fig. 1 – C). A rounded back may put pressure on structures at the back of the spine, including the intervertebral discs.
The other common sitting posture is most probably a result of the attempt to “sit up straight” as an overcorrection of the rounded posture due to pain (fig. 1 – A). A person will arch their back in and in the process cause excessive muscle tension in the back muscles as well as compression in the facet joints of the spine.
Ideally, when we sit, we want to sit in as neutral a position as possible (fig 2), maintaining the natural s-curve of the spine, and be able to do so without overly contracting the spinal muscles (fig. 1 – B). Sitting on the correct area of the pelvis will help facilitate this. The sitting technique we will use is a “Sit bone sit” https://youtu.be/3AQUWVKK4D8. As you sit down, reach around and pull back and up on the sit bones one side of the pelvis at a time. You should find now that you are sitting more on the front aspect of the sit bones with the weight more evenly distributed throughout the thighs. This will allow you to relax into the back of your chair without rounding the lower back and sit in neutral alignment without tensing the back muscles.
From here, reach up as high as you can with your arms to set the rest of the spine in a lengthened position then lower the hands and try to keep the spine in this rested position. Finally, look at the position of your knees; they should be at the same level. If one leg is further forward than the other, you may need to “scoot” this side of the pelvis back a little further.
If possible you should attempt to perform the Booty Scoot every time you sit down so that you are starting off in an optimal sitting position.
You should also make sure your chair is at a height that allows the knees to be slightly lower than the height of the hips and the feet should be flat on the ground. More vertically challenged employees may with to consider the use of a footrest if their feet do not touch the ground.