Swiss Balls And RSI

Wesley Priestley:

Hello everyone,

Allow me to go against the tide a bit here: Use of the larger size Swiss balls or other inflatable exercise balls may not be a totally bad idea. There are some advantages for intermittent use although I have to agree with Mr. Priebe in his overall assessment that the disadvantages are several.

In sitting, the lumbar "forward sway" (lordosis) needs to be maintained. This can be accomplished on a ball by rolling the hips forward on the ball, forcing the pelvis into an anterior tilt. This is the same concept employed in backless knee chairs of days past. It does not however, prohibit a slump posture which occurs when the hips are rolled to the back of the ball.

Also, the dynamic action of the spine is greatly increased compared to the static forces imposed in normal chair sitting. Every time you move you bounce. Each move side to side induces intervertebral motion.

Finally, the EMG or neuromuscular activity of the paraspinal muscles is far greater in this type of "unstable" sitting, eventually being more conducive to a strengthening effect. That is why we use the thing in the first place in clinics for stabilization exercises. Using the ball versus a good office chair produced a definite fatigue in my own back after about 20 minutes.

In summary, I would certainly use caution in the recommendation of such sitting but I would not rule it out. Especially for intermittent sitting in an otherwise healthy individual whom I can instruct in the principles of its proper use. But long term or as the only seating option....nah.

Wes Priestley

Senior Physical Therapist

Worker Evaluation & Restoration Center

University of Tennessee Medical Center

Knoxville, TN

Peter M. Budnick:

I'd like to submit a word of caution regarding the "ball" type chairs.

Greg Hart wrote:

The ball would more likely stimulate dynamic variation in trunk muscle contraction since it is slightly unstable in a multitude of directions.

In response, Wesley G. Priestley wrote:

Finally, the EMG or neuromuscular activity of the paraspinal muscles is far greater in this type of "unstable" sitting, eventually being more conducive to a strengthening effect.

Am I correct in assuming that it would be relatively easy to fall or roll off one of these "balls" when compared to a "5-star" base design common to office seating?

If so, any potential positive effects due to the unstable nature of the device aside, I would *never* recommend their use in the workplace, precisely because they are unstable. Introducing a safety hazard in an effort to address an ergonomic concern can be tempting, but I'd advise against it, especially in the United States (for liability reasons).

Peter

Peter M. Budnick, Ph.D., CPE

Richard Goggins:

This has been an interesting discussion, but it's starting to seem like one of those cases where we get caught up in considering a solution based on its biomechanical merits and forget about other important factors such as safety. A couple of postings have been in favor of using the ball because it is "unstable" and would provide for a more dynamic seated posture. However, unstable also means that sooner or later someone will roll too far on the ball and land on their head.

These balls may be fine for your own use, but employers have to provide safe equipment for their employees.

Rick Goggins

Ergonomist, Policy and Technical Services

Washington State Department of Labor and Industries

PO Box 44640

Olympia, WA 98504-4640

e-mail: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

phone: (360) 902-5450

Lee-Jean Lin:

it's starting to seem like one of those cases where we get caught up in considering a solution based on its biomechanical merits and forget about other important factors such as safety

I have to agree with Mr. Goggins and Budnick that safety should be a VERY important concern regarding this type of issues. Swiss balls are NOT meant to be used the way it was described in some previous e-mails. Sitting on a ball instead of a chair may be considered "mis-use of the product" or "unreasonable conduct." Manufacturers won't assume any liability if some body gets hurt when using the product in an unforeseeable fashion. (Have you ever seen a warning label such as "Don't sit on this ball" on the ball itself?) Anyway,the liability may rest on whoever recommends the mis-use of the product. Be very careful with your recommendation. It's no fun to be grilled by the plantiff's attorney and the court can very unforgiving.

Lee-Jean Lin, CPE

Principal

Canyon Ergonomics

Redondo Beach, CA 90277

(310) 792-0415

(310) 792-0436 fax

http://members.aol.com/CanyonErgo/Home.htm

Greg Hart:

This has been an interesting discussion, but it's starting to seem like one of those cases where we get caught up in considering a solution based on its biomechanical merits and forget about other important factors such as safety. A couple of postings have been in favor of using the ball because it is "unstable" and would provide for a more dynamic seated posture. However, unstable also means that sooner or later someone will roll too far on the ball and land on their head.

The reason that the discussion started out along the lines of physiology and biomechanics was because arguments based in those domains were advanced to marginalize this device.

These balls may be fine for your own use, but employers have to provide safe equipment for their employees.

As for the safety issue, which is always a wise point to consider, I am not convinced that the ball presents such a serious risk. When you are sitting on it, it is not so unstable that you would roll off of it very easily (probably less likely to fall asleep at your desk too!). Many of the balls have little feet that pop out when no one is on it which prevents it from rolling away.

The ball does not need to be necessarily considered as the only seating option and there are many situations where it would be clearly contraindicated. In the same spirit, it should also merit some serious consideration for its potential advantages. Research has been done in Europe with children sitting on the ball at school (over an entire school year) and there was no increased reporting of accidents attributed to the use of the ball.

Greg Hart, Kinesiologist