Anyone who spends hours at a desk every day risks neck tension and chronic back pain. A high-quality office chair is an important first step – but it only reaches its full potential when 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 should sit at belt height, and there should be a hand’s width of space between the back of your knees and the front edge of the seat. Use the built-in mechanism to avoid sitting rigidly.
Biomechanics: Why the right adjustment saves your spinal discs
Before we get to the measurements, here’s the “why”: when sitting, the pressure on the lumbar spine increases by around 40% compared to standing (Wilke et al., 1999).
- The sponge effect: Spinal discs are nourished not by blood vessels, but by diffusion (changes in pressure) (Holm & Nachemson, 1983). Sitting rigidly causes them to “starve”. Only dynamic sitting keeps them flexible.
- Isometric strain: Without correctly adjusted armrests, the shoulder muscles have to work extremely hard to support the weight of the arms (approx. 8 kg). This leads to painful myogelosis (muscle hardening).
Step-by-step guide: The perfect adjustment
Step 1: Seat height (The foundation)
Adjust the height so that your feet are flat on the floor. There should be an angle of at least 90° between your thighs and lower legs (with your knees at hip height or slightly below).
Rule of thumb: Seat height ≈ lower leg length + 3 cm (shoe sole)
| Height | Recommended seat height |
| 155 - 165 cm | 40 - 45 cm |
| 165 - 180 cm | 43 - 49 cm |
| 180 - 195 cm | 47 - 54 cm |
| Tip: If the desk is too high and your feet cannot reach the floor, a footrest is required | |
Step 2: Seat, depth and tilt
Use the full seat surface. Slide all the way back until your pelvis touches the backrest.
- Seat depth: There should be about a hand's width of space between the front edge of the seat and the back of your knees. This prevents pressure points and promotes circulation.
- Seat tilt: If available, tilt the seat slightly forward. This positions the pelvis correctly and helps prevent a rounded back.
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Step 3: Backrest and lumbar support
The lumbar support (the curved section of the backrest) is the heart of ergonomic seating.
- Position: It must sit exactly at the level of the pelvic crest (belt line). Only here does it provide the necessary support.
- Contact: Your upper pelvic area should always stay in contact with the backrest to relieve pressure on the spine.
Step 4: Adjust the armrests
Scientific studies show that correct arm support significantly reduces activity in the neck muscles (trapezius muscle), helping to prevent 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 desk surface. Your shoulders should stay relaxed and lowered (do not hunch them up!).
- Width: Your arms should rest close to your body to avoid a splayed posture.
Step 5: Headrest (Relief)
A headrest is not a “must”, but it is a real relief during long phone calls or extended screen time.
- Adjustment: It can be used as a neck support (in the natural curve) or as a headrest.
- Angle: Your head should be slightly lowered when looking at the monitor. The support is there to provide relief when you consciously lean back.
Step 6: Backrest tension (Activate movement)
This is the most important step for healthy sitting. Release the backrest lock!
- Resistance: Adjust the rotary knob under the seat so that the backrest gently supports you when leaning forward, while still allowing you to lean back without effort.
- Goal: The chair should follow your every movement like a “second skin”.
Dynamic sitting: The “lock” is the enemy
Many users make the mistake of locking the backrest in place (locked mechanism). “Studies show that dynamic sitting concepts activate the core muscles and significantly increase perceived comfort during long periods of screen work (van Dieën et al., 2001). Modern ergonomics therefore advises against it:
- Static sitting: Leads to one-sided strain and fatigue.
- Dynamic sitting: Promotes circulation and keeps the spinal discs active. Consciously alternate between focused forward work and relaxed leaning back.
Common adjustment mistakes (Quick fix)
- Seat too low: Causes the hips to “bend” and puts pressure on the abdominal area.
- Raised shoulders: Armrests are adjusted too high; result: tension headaches.
- Monitor too high: Causes neck stiffness. The top edge of the monitor should be at eye level.
- Lack of usability: When buying, make sure all levers are intuitive to use and easy to reach while seated (ideally with pictograms).
FAQ - Frequently asked questions
How long does it take to adjust?
Your body needs around 1 to 2 weeks to get used to a healthy posture. At first, you may experience mild muscle soreness – this is a sign that your muscles are becoming actively engaged again.
Should I use a gaming chair or an office chair?
A classic ergonomic office chair often offers more precise adjustment options for lumbar support and mechanism settings. Gaming chairs are often bucket seats and usually only have a tilt mechanism, which can restrict movement.
Is a standing desk necessary?
An (electric) height-adjustable desk is the perfect addition. The rule of thumb: 60 % sitting, 30 % standing, 10 % walking.
Conclusion: Ergonomic sitting is individual. A chair is no use if it is used incorrectly. Take these 5 minutes - your back will thank you.
References
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.