Office Chair Stool

The small stools used with office chairs have numerous adverse effects on lumbar health. It is not recommended to use them for extended periods, and even stools with backrests should be chosen with caution. An ideal lumbar-supporting chair should meet specific criteria.

Adverse Effects of Small Stools on the Lumbar Region:
Small stools used with office chairs are typically low in height. When sitting on them, the knees often rise above the hips, causing the pelvis to unconsciously tilt backward, leading to a rounded and forward-leaning back. This posture disrupts the natural curvature of the lumbar spine, significantly increasing the pressure on the intervertebral discs and lumbar back muscles. When sitting on a low stool, the pressure on the spine can be as high as 250% of that in a normal sitting position. Maintaining this posture for extended periods can easily lead to lumbar muscle strain, lumbar back muscle fatigue, and increased burden on the intervertebral discs. Additionally, sitting on low stools can increase the burden on the hip and knee joints, and for the elderly, it may also increase the risk of falls.

Limitations of Stools with Backrests:
Although stools with backrests can provide some support to the lumbar and back regions, helping to maintain posture stability and reduce the chance of strain, if the seat surface of the stool is too low, the backrest cannot change the issue of 'knees higher than hips and pelvis tilted backward.' The natural curvature of the lumbar spine will still be disrupted, and the risk of lumbar injury will persist. Therefore, stools with backrests but excessively low heights are also not recommended for prolonged use.

Criteria for an Ideal Lumbar-Supporting Chair:

1. Appropriate Height: After sitting down, both feet should be able to rest flat on the ground without hanging in the air; the thighs should be nearly horizontal, with the knees naturally bent, and the hips slightly higher than or close to the knees. Ideally, the thighs should be parallel to the ground, with the hips and knees forming an angle of approximately 90°.
2. Backrest: The chair back should preferably have a certain inclination, around 95° to 105°. When the waist is supported, the pressure inside the lumbar intervertebral discs is minimized. If the lumbar support is not suitable and the waist is left hanging, a cushion or rolled-up towel of moderate thickness can be placed behind the waist.
3. Stable Seat Surface: The seat surface should not be too narrow or short, nor should it be noticeably tilted or wobbly. After sitting down, the buttocks and thighs should receive sufficient and stable support.
4. Regular Breaks: No matter how standard the sitting posture is, prolonged sitting can stiffen the lumbar muscles. It is recommended to follow the '30 to 45-minute break rule,' getting up to walk around and stretch every sitting period.