Many people spend the majority of their waking hours sitting—at home, commuting, and at work.

Particularly when we’re sitting for long periods at a desk, there are a few things we should keep in mind.

How should we sit?

Many people think there is one “good” posture. But actually, there isn’t just one way of sitting. Different ways of sitting will place different physical stresses on our bodies, and variety is good.

To work out if a posture is “good” or not, we can assess it based on several things:

the amount of muscle activity required to hold the position (too much muscle activity could be a problem as it can result in fatigue if held continuously for a long period)
the estimated stress on joints, including the discs between the vertebral bones of the spine (too much physical loading stress could be a problem as it may cause pain in the joints and ligaments or muscles around them)
whether the joints are in the middle of their range of movement or near the extreme (awkward, near end-of-range postures may put more stress on tissues around joints)
the amount of fidgeting people do (moving about in your seat, or fidgeting, can be an early indicator of discomfort and may suggest a risk of later pain).

Given these criteria, research suggests there are three main options for how you can sit well at a desk. Each option has different pros and cons, and is suitable for different tasks.

Option 1: upright sitting

This is probably the posture you think of as “good” posture. The defining feature of this option is that the trunk is upright.

A key component of upright sitting is that the feet can comfortably rest on a surface, whether the floor or a footstool. This position also makes it easy to adjust posture within the chair (fidget) and change posture to get out of the chair.

It’s also important the arms hang down from the shoulders verticallywith elbows by the trunk, unless the forearms are supported on the work surface. Holding unsupported arms forward requires the muscles connecting the shoulder and neck to work harder. This often results in muscle fatigue and discomfort.

The head should be looking straight ahead or a little downwards. Looking upwards would increase tension in the neck and likely lead to discomfort.

This posture is useful for common office tasks such as working on a desktop computer.

Option 2: forward sitting

The defining feature of this posture is that the trunk is angled forward, and the arms are rested on the work surface. Allowing the thigh to point down at an angle may make it easier to maintain an inward curve in your lower back, which is suggested to reduce low back stress.

For a time, special chairs were developed to enable the thigh to be angled downwards, and usually had a feature to block the knees, stopping the person sliding off the angled seat base.

By perching on the front of an ordinary chair and resting your elbows on the work surface, you can use this posture to provide variety in sitting. This posture is useful for tasks such as drawing or handwriting on a flat work surface, either with paper or a touch screen device.