ergo equipment Apr 30, 2019

Is sitting not as bad as we all think? Let’s get real before we dive into this post. 

There is some controversy whether or not prolonged sitting in general causes lower back pain. We need to get this settled before we can get into any in depth analysis about the benefits of ‘active’ type chairs. Looking at the evidence, there is a high instance of correlation between work related musculoskeletal symptoms in the lower back – and depending on where you find the information it can be anywhere between 20% and 55% prevalence. Personally I view this as enough evidence to support finding novel solutions that can actively or passive improve long-term lower back health and that’s where today’s post fits in…

This blogpost is based off of this research, that examines a few different types of chairs and offers valuable insights that can help you when you are doing assessments or looking at what features to consider when you are in the market for a new office chair.

Prevention is the treatment of choice.

That’s the whole theory with these types of chair. Obviously the biggest value will be getting up, walking etc. However, optimizing sitting when there’s a need can make sense for some people.

The Rotavis ‘active sitting’ chair

What is ‘Active’ Sitting?

Let me explain this with a comparison.

A typical office chair only has a back to forth motion and can be thought of a rocking chair for the office. Note: Interestingly, the specific type of movement that this is called will vary based on where you are located in the world – in North America a popular way to refer to this movement is a ‘Synchro-Tilt’ feature. While this can be perfect for helping young children get to sleep (twin mom here, so I totally appreciate that…), it really doesn’t do it for optimizing health. When you think about it, there’s only one degree of motion that a ‘typical’ office chair offers, and that’s back and forth (just like a rocking chair). This merely changes the hip flexion angle and the orientation of the spine. Don’t get me wrong, this movement is better than nothing, but my question for this post is that can this be improved? In our modern time most of us are still using, functionally, our grandmother’s office chair. It’s this relative comparison that best describes what ‘active’ sitting is.

Active sitting is kind of like sitting in a super-futuristic, multi-directional seat pan- rocking chair.

An ‘active sitting’ chair is about providing both a passive and active method to cycle out waste products from our intervertebral discs to ensure that we can optimize long-term back health. It’s an unstable sitting surface that can move in multiple directions because this has shown to be better for long-term lumbar (lower back) intervertebral disc health. That hopefully means less risk for back pain!

Let’s get into the biomechanics of sitting 

To maintain an upright sitting posture, constant muscular effort is needed and it doesn’t take a lot of effort to lead to fatigue. Lower back pain is hypothesized to be prevalent among office workers due to monotonous low level mechanical loads on the spine and other joint tissues while seating as well as the accumulation of metabolites in the intervertebral discs, accelerating disc degeneration and leading to disc herniation.

Let’s put a few things in perspective:

  • A chair will never replace full body movement. As research says there is a major benefit in limiting the amount of time that you sit still for in a day. This should always be kept in mind no matter what type of chair that is being used. Depending on the person, it’s recommended that they get up from sitting every 45 – 60 minutes.

This research that I’m going to share with you today is all about how to optimize the sitting experience. The thing that I really want to highlight about this research is that I’m not going to share details about subjective feelings; I’m going to talk about the cold, hard facts of active chairs (although comfort does play a role here too).

Backrest contact really is important

No matter what chair is being used, making firm (yet comfortable) contact with the chair’s backrest is key for long-term health. The backrest is so important to active chairs (or really any office chair for that matter). This is based off not only the ergonomic standards, my personal preference, and that the research is pointing out that office workers prefer them too. This research interestingly found that the missing upper body stability is hypothesized to be the reason why office workers do not use backless active chairs in an active manner during computer based office work.​ Interesting, isn’t it?

There’s a fine line between just enough pelvic chair movement (aka instability in the seat pan) and allowing that person to have a stable upper body posture to use their backrest support. As this research says, in most cases people will prefer to use a chair with a backrest because they find it to be more comfortable. Additionally, there seems to be ‘just the right’ amount of movement for a chair: too much pelvic (or seat) motion chair can make it less likely for that person to use the backrest. On the other hand, a stable thorax (upper body) and head posture is essential to ensure full concentration on that person’s working tasks at the same time as using the backrest as this research states. It seems you can’t have one without the other, and there is always a user preference to what degree of motion that they are comfortable with. I can’t emphasize enough to try these chairs out for as long as possible (2 weeks would be useful) before making the purchase.

Here’s what this research says works best with an active sitting chair: a robust potential seat range of motion (must be able to be controlled by the user) while having a stable upper body posture with a backrest.

Conventional office chairs don’t promote this.

Something to consider when looking at these types of chairs. This research says is that people preferred the active chair type that had the centre of gravity below the motion axis. This allows the office worker to sit in a stable position while working and needs no muscular effort to keep the seat in the middle position. It’s almost that it creates a level of certainty that people really appreciate and encouraged them to use the chair more (especially when compared to other active sitting chairs).


Let’s talk about the big picture here. There are some really interesting points about active sitting. No matter how amazing these products are they will never replace activity and it’s my opinion that if you have the budget for these types of chairs they can be amazing. Everyone else must be incorporating less seated postures or sedentary activities in general. That means limiting sitting to between 45 and 60 minutes at one time. I realize that this is a behaviour change and some may argue this, however we cannot ‘engineer’ out risks to long-term back health – even with an active chair one must remember to use its ‘active function’.

One last thing that I need to share... the active sitting component of the chair should not compromise the ergonomics of the workstation. And in this case, we’re talking about the position of the user’s head. If there’s too much movement as a result of the movement at the pelvis (seat pan area of the chair) that person may be using static non-neutral neck positions to view the monitor. This of course is an ergonomics risk for neck discomfort. This study found that the neck remained within acceptable ergonomic guidelines even during lateral spine flection of more than 10 degrees active sitting chair – so that’s something to keep in mind when looking at active chair options.

What Do You Think?

Do you or would you recommend these types of chairs if your client reports lower back pain? If not, what are the barriers standing between these types of chairs and your client? Let me know in the comments below!


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