Jan Tissing can’t stand it when he sees people in poor postures. As a physiotherapist and ergonomic consultant to companies around the world, he frequently sees work postures compensating for ineffective chairs.
“This affects not only your back and arms, but your head and neck too. The cervical spine, from the shoulders up, is a marvel of engineering, holding the head and supporting all our senses. But if your neck has to flex forward to hold your head, as it often does when you work on desktop screens, tablets and laptops, the cervical spine will deform rapidly. In my opinion, sitting is a fine way and, most of the time, the best way to perform tasks. But many chairs haven’t kept up with how we use technology, the frequent collaboration, and the different postures we assume throughout the day.”
Given these trends, Steelcase asked Tissing to evaluate the Gesture chair, the first office chair designed to support a greater range of technologies, postures and sizes. How well does Gesture, including its new headrest, perform for today’s multitasking, tech-wielding knowledge worker?
“Sitting is a fine way and, most of the time, the best way to perform tasks.”
A HEALTHY POSTURE
Tissing says good seated postures have many benefits. “We know that the human body can command an enormous repertoire of sitting postures. That’s why people have different preferred working positions. So I don’t look for a single, best posture; I look at the impact on the skeleton, muscles and blood flow.”
He says a healthy seated posture:
- Supports an angle of 100º or more between the hips and spine
- Maintains the spine’s natural S-shape
- Supports the head centered on the neck, not leaning forward
- Puts no pressure on internal organs
- Helps maintain healthy blood flow in the body
EVALUATION
Tissing and his team evaluated the Gesture chair with headrest in use by 22 test subjects, men and women between the ages of 23 and 61. Each person used Gesture from three to 10 hours during a typical workday.
Users were not told how to adjust Gesture or even how to sit with proper posture, only that they would be photographed while working. A high-definition video camera captured each user’s position every 30 seconds, documenting how they worked, moved and interacted with colleagues as well as with the Gesture chair. The users were also observed and recorded while working in the chair they normally use at work each day.
Tissing says most of the users’ regular chairs caused the natural S-curve of the spine to “deform” into a C-shaped curve. As people leaned toward their digital devices, the upper body inclined forward and the head and neck moved ahead of the back. “This has negative effects on the spine and discs. The lungs are pressed together and the bowels start to crowd the thorax (chest) area.”
Some had chairs without armrests, or with armrests that are difficult to adjust, “which caused users to sit forward and assume a poor posture.”
Another issue he saw with the test workers’ chairs: back tension adjustments were difficult to find and use. Some users lacked the weight or heft to recline the seat back, or didn’t know how to adjust back tension, so the back remained in the upright position. That meant users could not recline and reduce the pressure on the sitting bones and more evenly distribute that pressure throughout the upper body.
Headrests were lacking on most of the users’ chairs too. “Few standard task chairs have a headrest. It’s typically added as an upgrade to create a manager chair,” says Tissing, who believes headrests should be more widely available (see sidebar, left).
In fact, when Tissing gave users brief instructions in chair use and posture, or showed them time-lapse images of themselves at work, they assumed more reclined postures and took advantage of the Gesture chair back and headrest, more so than when using other chairs.
The Gesture headrest is the first headrest that supports a greater range of technologies, postures and sizes. It is especially supportive in applications with external monitors and supports users by allowing them to recline and work while keeping the head and neck centered over the spine.
RESULTS
Tissing and his colleagues grouped the results of the study by specific chair adjustments and their support for different parts of the body. Here are their findings.
Seat Height
Gesture’s range from 406 to 533 mm (16″–21″) easily fits males from 157 to 200 cm (approx. 5’2″– 6’7″) and females 153 cm to 197 cm (approx. 5’– 6’6″). That’s 99% of all workers.
Seat Depth
Gesture’s seat-depth adjustment (70 mm / 2.75″), together with its shape and soft edges, accommodates users from 149 to 200 cm (approx. 4’11″– 6’6″) in height. Seat comfort, the smoothness of the mechanism and the backrest combine to provide good comfort and support. Even when reclined in the Gesture chair, users found no need to reposition themselves after long periods.
Lumbar Support
Advanced, automatic lumbar support, combined with Gesture’s capability to adapt to weight differences between users and its inviting armrests, give the standard Gesture an advantage over many other chairs.
Adjustable Armrests
Easy and intuitive to use. A single button adjusts height and activates 360˚ motion of width, depth and pivot. The pivoting feature is unique: it supports the arm and shoulder in its natural movement and doesn’t force the shoulder into protraction or other uncomfortable positions.
Headrest / Neck Rest
Adding the advanced design headrest to Gesture’s already slightly higher back invites the body, especially the upper thorax and lower cervical region, to lean back and relax. The head is balanced on the torso.
The highly adjustable neck rest makes a difference to the user; the neck rest can be positioned very easily in every position with height, forward and tilting adjustments. It’s easy to adjust: just grab with two hands and adjust it to your head. Plus, it supports the same range of sizes as the standard chair, 99% of the population.
Mechanism Adjustment
Often it’s difficult to find a mechanism that can fit all users. For example, a small user might not have the weight to move the chair out of an upright position. Gesture really fits all users, and invites them to relax. The tension knob on the mechanism needs only four full turns to go from lightweight to really heavy. Even in the most upright position, there are a few degrees of movement of the back, just enough to comfort the body in a way that those who only want to sit in a fixed chair are pleasantly surprised.
General Adjustment
People tend to test a maximum of three knobs up to three times. Manuals are most often not read. Gesture has two turning knobs and no buttons to pull or push.
All controls are located together on the right side of the chair. The single knob for each armrest is easy to find and works well. The neck rest has no knobs; just grab and position. You can even do part of it without your hands.
Summing up, Tissing believes that “today, there’s no reason to sit in a chair from the equivalent of the horse-and-buggy era when you can use a hybrid car that offers speed, comfort and safety.”