Zavitz on Ergo:
The Latest Fad in Office Ergonomics: Exercise Balls

by Ben Zavitz, CPE

You’ve seen them, right? Those $20 exercise balls

that everyone at the local gym and PT (Physical Therapy) clinic are using to improve core strength? This particular type of exercise equipment has been increasing in popularity, not only in the gym but at work, too. I'm sure everyone has seen, or knows someone who sits on one of these inflatable balls (also know as FitBalls, Swiss Balls, Physio Balls, or Stability Balls) and swears that sitting on the ball is far superior than in a chair. I recently noticed that an employee at a client site was sitting on a ball. When I asked her about it, she showed me all the cool positions she could sit in (some of those positions looked like she was riding a mechanical bull). Is it possible that this new fad is both beneficial and cost effective?

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About Zavitz on Ergo
Zavitz on Ergo is a quarterly column in Priority Press, addressing ergonomics issues and trends. If you have questions you'd like to see answered in future editions, send them to Ben Zavitz at zavitzb@eorm.com.
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Before we answer that question, we need to understand some facts about the ergonomics of seated work.

Science of Seated Work

Studies have been conducted over the years on the ergonomics of seated work. Here are the highlights of their findings:

Benefits of a Ball

According to Jane Clapp, co-author of Working on the Ball, combining fitness with work results in a balanced lifestyle for people who have little time to go to the gym. In her book she comments, “The majority of our clients have jobs that require them to sit at a desk all day. It came to our attention that the more time they spend at work, the less energy, time and motivation they had to make it to the gym.” Clapp believes that using a stability ball as a chair at work improves coordination, core strength, and makes people more alert throughout their day. How is this possible? Well the ball requires active sitting (which is different than ergonomic sitting). Active sitting requires continuously maintaining your balance while engaging several muscles throughout your body. In other words, you are using balance and your core strength (primarily abdominals and spine stabilizer muscles) to keep you in the correct position (lumbar lordosis).

Are Exercise Balls Effective?

In a recent university study where muscle activation levels (using 8 channels of electromyography) and 3D lumbar spine motion were recorded while subjects sat on a stability ball and a standard office chair (without arm rests) found no advantage to using the stability ball as an office chair. The results found an increase in muscle activation in the thoracic erector spinae muscle (increased levels of muscle activation were found in the other muscles, but they were not significant), decreased pelvic tilt, and increased perceived discomfort while sitting on the stability ball. Based on their findings the authors concluded that the small biological responses when sitting on a ball compared with an office chair, combined with the increased discomfort while on the ball, and the potential safety issues associated with sitting on an unstable surface question the use of a stability ball as an office chair and that its use for prolonged sitting may not be advantageous.

And Finally…

Based on the above facts, the best guidance I can give you is that stability balls are not an effective solution for reducing low back pain in the workplace because of these reasons:

  1. Active sitting increases the rate of fatigue due to constantly challenging your balance. In addition to fatigue, continuously maintaining your balance throughout the day may be an issue for some individuals and people with previous back injuries who have decreased postural control.

  2. Balls do not have a stable balance and present a potential safety risk of falling off them.

  3. Balls do not have armrests or back supports, key features in supporting the body.

  4. A reclined sitting position produces the least amount of disc pressure and muscle activity – this cannot be achieved with a ball.

The best way to reduce low back fatigue and discomfort from sitting is to limit prolonged exposure to sitting to one hour (every hour stand up and maintain a relaxed position for 10-20 seconds) and chose a chair that allows you to change your sitting posture frequently throughout the day.

Before implementing any solution in the workplace, attention to the details in the design, layout, work methods/job tasks and the associated postures of the neck, shoulders and upper extremities need to be evaluated to ensure that ergonomic risk factors are not being introduced that would increase the risk of a Work-related Musculoskeletal Disorder (WRMD).

If you have ergo questions, comments, or topics you’d like this roving columnist to cover, email me at the address below. Watch your back this summer!

Ergonomically Yours,

Ben Zavitz, CPE
EORM, Inc.
zavitzb@eorm.com.
tel: 781.938.9152 ext 106

Edition No. 17

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