Workspace Ergonomics: Chair Design

(5 min reading time)

INTRODUCTION

A comfortable chair can make or break your work day (not to mention your back!).  We have compiled this article on some aspects of ergonomics and have provided technical information on what makes a chair ergonomically viable.

ERGONOMICS

It is important to note that ergonomics is not an exact science and that ergonomists don’t agree on much!  However, what we DO know is that the spine has four principle curves: (cervical, thoracic, lumbar and pelvic).

These curves form the holy grail of the ‘S’ shaped spine:

workspace ergonomics chair design
Healthy ‘S’-curve Spine
  • Cervical
  • Thoracic
  • Lumber
  • Pelvic/Sacrum

OUR DEFINITION OF AN ERGONOMIC CHAIR

A chair that has been designed to morph to you, to flow, to work, to support, to change, to breathe with you. You could describe its motion as fluid, natural and balanced.  We think this is a good thing!

It should, we believe, do all this in a covert way rather than screaming ‘look at me’.  It should do all this, all day – every day – by design.

WHY IS IT UNHEALTHY FOR US TO SIT FOR TOO LONG?

  • Humans are not designed to sit.  To do so for long periods is a challenge as a static posture is not good for the body.
  • Movement is vital for the spine as this area has no independent circulatory supply.
  • Movement pumps nutrients into the spine and promotes good health.  Maintaining a neutral relaxed posture is key.
  • Sitting upright holding the ‘S’ shape of the spine all day long (unsupported) is not possible.  Most of us end up with a ‘C’ shaped spinal posture at the end of the day.
  • Prolonged bad posture and lack of spinal support leads to more mental and physical health complications than most of us realise.

CONSEQUENCES OF BAD POSTURE

  1. Worsens depression and stress.
  2. Digestive issues such as acid reflux and hernia.
  3. Poor breathing linked to lack of blood and compromised oxygen flow.
  4. Back, shoulder and Neck Pain.
  5. Tension headaches.

All of the above leads to hefty medical bills as well as compromised vitality.

PROBLEMS WITH MODERN SEATING DESIGN

The problem with most modern seating design is that it focuses primarily on pelvic support and dimensional adjustment for the lumbar region in terms of height but also to a rigid fixed depth.

Most chairs today seek to cater for 90% support but in truth get closer to only 80%.  Dimensional options are focussed on the seat, lumbar region and the arms.

Beyond this it is more often the aesthetic considerations that guide the design of the upper back profile.

Historically chairs are constructed using structural plastics and moulded foams.  Rigid frames with mesh type materials stretched across them tend to ‘hammock’.  This provides little intentional support.

Throughout Northern America and Central Europe the synchronous mechanism in its various guises is widely acknowledged as being the most suitable solution.  However, most users struggle to adjust the tilt tension effectively to balance the chair or ignore this adjustment entirely.  Users then revert to locking, which negates the benefits of the synchronous tilt.

Few chairs provide any adjustable dimensional support for the thoracic region of the spine.  As well as this lack, few chairs provide any effective dimensional support for the cervical spine as most headrests available today serve as status symbols –  rather than being functionally effective.

Research has shown individuals using a visual display terminal (VDT) prefer to work in a semi-reclined posture in a range up to 10° from vertical. Unsupported this causes a flattening of the upper spine and tension in the shoulder and neck muscles.

The build-up of heat in the muscles and tissue surrounding the sitting bones  (ischial tuberosity) and the back muscles lead to discomfort.  The flow of nutrients becomes restricted causing fatigue and long term health issues.

It is vital to choose a chair that supports the natural functioning of your spine.  You should be able to adjust the height of your chair so that your feet rest flat on the floor with thighs parallel to the floor. Armrests need to be adjustable and shoulders relaxed.

EXAMPLE OF AN ERGONOMICALLY SOUND OPERATOR’S CHAIR

office ergonomics

i-Workchair has the ability to replicate a wide range of movements with ease and comfort. Utilising a new generation of synchronised tilt action, i-Workchair mirrors the body’s natural pivot points, providing a seamless transition between upright and reclined postures.After looking at the way we work, this intelligent solution has been developed to respond to the new range of postures seen in the modern working environment.

We don’t sit still as we work…we reach, tilt, flex and lean.

Although we may think we sit still at our desks, we actually move more than we realise.

The back of the i-Workchair has the ability to flex and move even when in a locked position, as well as supporting a level of sideways and rotational actions that facilitate good spinal health as we sit and work.

Ergonomic Office Chair
i-WORKCHAIR Ergonomic Operator’s Chair
  • Utilising a multi layered approach, i-Workchair features a 3D perforated cut foam structure encased in two layers of elastomeric knitted fabric.
  • This optimises comfort while allowing excess heat to vent away from the back muscles, reducing fatigue.
  • i-Workchair provides an anatomically contoured dual density seat for exceptional comfort.
  • As we move our back, our arms move with us and it is this fluid motion that inspired the design of i-Workchair.
  • The chair’s central column and arms are joined through an innovative aluminium bridge. This then connects to flexible mounting bushes that allow the back a higher range of flexibility.
  • The aluminium bridge is a key structural component of the chair – elegantly connecting the seat, back and arms. This affords a greater degree of movement to support our  ever shifting posture.

The user is supported whether working upright at a desk, when leaning back using a handheld device, or simply when relaxed and reclined.

WHY ARE THE ARMS OF AN OPERATOR’S CHAIR IMPORTANT?

The arms of a chair can be crucial to supporting the entire upper body, but given the individuality of users, most chair arms fail to respond well and often become an obstruction to fluid movement.

With i-Workchair, the back, arms and central column are connected to the bridge, which means they move together in unison, offering a continuity of support.

A broad range of adjustments create a tailored sit for any size or shape of individual. The unique movement in the multi-dimensional arms allows the user to comfortably position them to support a variety of positions and tasks.

Width Adjustment: The two stage adjustment of the arm pad provides a broad range of functional width adjustment

Four Dimensions: With the upper pad in its forward position it can be rotated by up to 70 degrees providing additional width adjustment and support for the use of mobile devices.

For more information on our i-Workchair, watch this (3 min) video:

OTHER FACTORS TO TAKE INTO CONSIDERATION WHEN ASSESSING WORKSPACE ERGONOMICS

We’ve looked at ergonomic chair function.  Here are some other factors to take into consideration when assessing workspace ergonomics:

ergonomic office
Workspace Ergonomics

Keep primary task objects eg telephone and stationery within reach.  Stand up to reach for objects that cannot be comfortably reached for whilst sitting.

Keyboard and mouse: Place your mouse on the same surface as your keyboard and within easy reach.

Keep wrists straight and upper arms close to your body when typing and using your mouse. Hands should be at elbow level, or slight below.

Telephone: avoid cradling the phone between your head and neck.  Use a headset or place your phone on speaker.

Desk: ensure enough clearance for knees, thighs and feet. Use a height-adjustable desk and/or chair.

PC Monitor: must be directly in front of you, approximately an arm’s length away. The top of the screen should be at or slightly below eye level. The monitor should be squared with your keyboard.

TIPS to reduce extended mouse use

  • Use keyboard shortcuts
  • Adjust mouse sensitivity to avoid strain
  • Use alternate hands to operate your mouse

IN SUMMARY

We are all unique and so are the demands we place on our furniture. Choose a chair that has been specifically developed to allow you a greater range of adjustment.  This will give you maximum comfort during your work day.

The health benefits of ‘active sitting’ are well studied. Using an ergonomically designed chair encourages the user to engage muscles and regularly vary posture.

Our backs are a wonderful example of nature’s engineering…..our chairs should reflect that!