How to Sit With Lower Back Pain

Why "sit up straight" is unhelpful advice

Rigid upright sitting is a muscular effort. You can hold it for a few minutes, and then your postural muscles fatigue and you slump - usually into something worse than where you started. The useful goal is not a perfect posture held by willpower; it is a chair setup that makes a reasonable posture the path of least resistance, plus regular changes of position.

Everything below assumes you already sit at a desk with a chair that has at least a height lever. If it does not, skip to the section on chairs with no controls.

The six adjustments, in order

Do them in this order. Each one changes the right answer for the ones after it, which is why people who adjust randomly never converge on anything.

1. Seat height, from your legs. Stand in front of the chair. The seat pan should be at about the height of the crease behind your knee. Sit down; your feet should be flat with your thighs roughly level or sloping very slightly downward. If your feet dangle, the chair is too high - if it will not go lower, you need a footrest, and if it will not go higher, see the seat height table.
2. Seat depth. Sit all the way back against the backrest. You want one to two fingers of clearance between the front edge of the seat and the back of your knee. Too deep and you will slide forward and slump; too shallow and your thighs are unsupported. Full method in the seat depth guide.
3. Lumbar height. Find the inward curve of your lower back with your hand. Set the lumbar pad so it sits at that point - not above it, where it pushes your mid-back forward, and not below it, where it pushes your pelvis forward. If your chair has no lumbar adjustment, a rolled towel or a strapped cushion at that height does the same job.
4. Backrest angle. Set it slightly past vertical - somewhere around 100 to 110 degrees - and lean into it. Sitting bolt upright unsupported puts the whole load through your spine; reclining slightly transfers a real part of it into the chair.
5. Tilt tension. Set it so you can rock back with a normal push and the chair holds you without either flopping or fighting you. Most people leave this at the factory setting, which is calibrated for someone who is probably not your weight.
6. Armrests, last. Sit with your shoulders relaxed and down, elbows at your sides bent to about ninety degrees. Raise the armrests until they just meet your forearms at that position. If they force your shoulders up, they are too high. If you cannot reach them without leaning, bring them inward if the chair allows it.

What to do if your chair has no controls

Plenty of people are sitting on a fixed chair they cannot change - a dining chair at a kitchen table, a fixed chair at an office. You can still fix three of the six:

• Effective seat height: a firm cushion raises you; a footrest or a stack of books lowers your effective height by supporting your feet.
• Effective seat depth: a firm cushion behind your lower back moves you forward, shortening the pan.
• Lumbar support: a rolled towel is genuinely as effective as a purchased cushion, provided you put it at the right height and keep it there. A strapped cushion stays put, which is its one real advantage over a towel.

Changing position is the part everyone skips

The best-set-up chair in the world, sat in motionless for eight hours, will make your back hurt. The load has to move. Practical ways to make that happen without a productivity theory:

• Take calls standing. This alone breaks up most days.
• Recline for reading and sit forward for typing. Two postures beats one good one.
• Put the printer, the water, or anything else you need regularly somewhere that requires standing up.
• If you have a second seat - a kneeling chair or a stool - alternate rather than choosing.

We look at what the published guidance actually says about sitting duration, and where it is weaker than commonly claimed, in how long should you sit in an office chair.

Positions that reliably make it worse

• Perching on the front edge with no back contact. Common when the seat is too deep. All the load, none of the support.
• Sitting on a wallet, phone, or one folded leg. Tips the pelvis and loads one side.
• Crossed legs for long stretches. Rotates the pelvis and the lumbar spine with it.
• Laptop on the lap on a sofa. The worst combination available, and the one most people spend their evenings in after fixing their desk.

If the setup does not help

Give any change a week before judging it - bodies adapt slowly and the first two days of a new position often feel worse. If a week of correct setup changes nothing, the chair was probably not the driver. At that point the useful questions are whether the chair physically fits you (see the body fit hub), and whether what you have is desk-related ache at all.