Anyone who spends hours at a desk every day risks neck tension and chronic back pain. A high-quality office chair is an important start - but it only develops its full potential if it is precisely adjusted to your body.
The quick check:
To adjust an office chair ergonomically, follow the 90 degree rule: feet flat on the floor, knees and elbows at right angles. The lumbar support sits at belt height, and there is a hand's width free between the back of the knee and the edge of the seat. Use the built-in mechanism to avoid sitting rigidly.
Biomechanics: Why the right setting saves your intervertebral disc
Before we get to the measurements, the “why”: When sitting, the pressure on the lumbar spine increases by approximately 40% compared to standing (Wilke et al., 1999).
- The sponge effect: Intervertebral discs are nourished not by blood vessels, but by diffusion (pressure changes) (Holm & Nachemson, 1983). Sitting rigidly causes them to “starve”. Only dynamic sitting keeps them elastic.
- Isometric loading: Without correctly adjusted armrests, the shoulder muscles work hard to support the weight of the arms (approx. 8 kg). This leads to painful myogelosis (muscle hardening).
Step-by-step instructions: The perfect adjustment
Step 1: The Seat Height (The Foundation)
Adjust the height so that your feet are completely on the floor. There should be an angle of at least 90° between the upper and lower legs (knees at hip height or slightly below).
Rule of thumb: Seat height ≈ lower leg length + 3 cm (shoe sole)
| Body size | Recommended seat height |
| 155 - 165 cm | 40 - 45 cm |
| 165 - 180 cm | 43 - 49 cm |
| 180 - 195 cm | 47 - 54 cm |
| Tip: If the table is too high and your feet do not reach the floor, a footrest is necessary | |
Step 2: Seat, Depth and Tilt
Make use of the entire seating area. Slide all the way back until your pelvis touches the backrest.
- Seat depth: There should be about one Hand's breadth of space stay between the front edge of the seat and the back of your knees. This prevents pressure points and promotes blood circulation.
- Seat tilt: If available, tilt the surface slightly forward. This tilts the pelvis into a healthy position and prevents the hunched back.
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Step 3: Backrest and lumbar support
The lumbar support (the curvature of the backrest) is the heart of ergonomics.
- Position: It must sit exactly in the area of the iliac crest (belt line). Only here does it offer the necessary stability.
- Contact: The upper pelvic area should always remain in contact with the backrest to relieve the strain on the spine.
Step 4: Adjust armrests
Scientific studies show that correct arm support significantly reduces the activity of the neck muscles (trapezius muscles) and thus prevents chronic tension (Aarås et al., 1997).
- Angle: Adjust the height so that your upper and lower arms form a 90° angle.
- Position: The armrests should be level with the table surface. The shoulders must remain relaxed and down (do not pull up!).
- Width: The arms should be close to the body to avoid a splayed posture.
Step 5: Headrest (The Relief)
A headrest is not a “must”, but it is a blessing for long phone calls or screen time.
- Setting: It can be used as a neck support (in the curve) or as a headrest.
- Angle: Your head should be slightly bowed when looking at the monitor. The support serves as relief when you consciously lean back.
Step 6: Counterpressure of the mechanics (activate dynamics)
This is the most important step for healthy sitting. Open the backrest lock!
- Resistance: Adjust the knob under the seat so that the backrest gently supports you when you bend forward, but you can lean back without any effort.
- Goal: The chair should follow your every movement like a “second skin”.
Dynamic sitting: “Locking” is the enemy
Many users make the mistake of locking the backrest (locked mechanism). "Studies show that dynamic seating concepts activate the core muscles and significantly increase subjective comfort during long periods of computer work (van Dieën et al., 2001). Modern ergonomics therefore advises against this:
- Static sitting: Leads to one-sided strain and fatigue.
- Dynamic sitting: Promotes blood circulation and keeps the intervertebral discs active. Consciously alternate between concentrated preparatory work and leaning back and relaxing.
Common errors when setting (Quick Fix)
- Seat too deep: Leads to the hips “kinking” and puts strain on the intestinal area.
- Shoulder elevation: Armrests are set too high; Result: tension headache.
- Monitor too high: Causes neck stiffness. The top edge of the monitor should be at eye level.
- Lack of usability: When purchasing, make sure that all levers are intuitive and can be reached while sitting (ideally with pictograms).
FAQ - Frequently asked questions
How long does it take to get used to it?
Your body needs about 1 to 2 weeks to get used to a healthy posture. At first you may experience slight muscle soreness - this is a sign that your muscles are working actively again.
Should I use a gaming chair or an office chair?
A classic ergonomic office chair often offers more precise adjustment options for the lumbar and mechanics. Gaming chairs are often bucket seats and only have a rocking mechanism, which can restrict movement.
Is a standing desk necessary?
An (electrically) height-adjustable desk is the perfect addition. The rule of thumb: 60% sitting, 30% standing, 10% walking.
Conclusion: Sitting ergonomically is individual. A chair is no use if it is used incorrectly. Take these 5 minutes - your back will thank you.
Bibliography
Aarås, A., et al. (1997). Musculoskeletal, visual and psychosocial stress in VDU work: a prospective epidemiology study. Applied Ergonomics.
Holm, S., & Nachemson, A. (1983). Variations in the nutrition of the canine intervertebral disc induced by motion. Spine.
van Dieën, J.H., et al. (2001). Effects of dynamic office chairs on trunk kinematics, trunk muscle working and self-reported comfort. Applied Ergonomics.
Wilke, H.J., et al. (1999). New in vivo measurements of pressures in the intervertebral disc in daily life. Spine.