Zavitz on Ergo:
Back Belts: Friend or Foe?
by Ben Zavitz, CPE
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Way too early last week, I woke up to loud jackhammering in front of my house. Later, as I sat bleary-eyed and drank my coffee, I noticed several guys demolishing my neighbor’s sidewalk and ripping up his front yard to install new landscaping. Several of the workers were wearing back belts. As an ergonomist, this piqued my interest since I thought most people gave up using back belts to reduce back injuries eons ago. Old technology, I said to myself----these guys must be from the Stone Age. Shortly after this experience, I received an email from a client asking my opinion on using back belts as a way to prevent injuries. Have I missed something? Is this a new trend? Is there a new back belt out there that is fashionable? Here’s what I found out.
Background
Back belts, which come in several different types or styles, (e.g., leather, elastic, and inflatable) are also known as back supports, abdominal belts, lumbar supports, or industrial back belts. The manufacturers and endorsers of these products claim the following benefits.
- Helps workers remember to lift properly
- Provides warmth to the lumbar region
- Reduces muscular fatigue
- Acts as a splint, reducing range of motion and decreasing the risk of injury
- Reduces compression forces on the spine by increasing intra-abdominal pressure
- Supports shear loading on the spine when the upper body is bent forward
Scientific Studies
Over the years, many studies (clinical, biomechanical, physiological and psychophysical) have been conducted on the occupational use of back belts. Here are some of the highlights:
Clinical Studies
The data from a few of the better executed clinical studies indicate the following:
- The universal prescription of back belts for uninjured employees involved in material handling activities to prevent back injuries is not supported.
- Weak evidence suggests that already injured employees may benefit from wearing a back belt to reduce the risk of recurrence.
- The risk of injury increases following a period of time after a trial of belt use.
- The severity and cost of a back injury may be higher in employees who wear belts compared to those who don’t.
Biomechanical Studies
Biomechanical studies have primarily focused on intra-abdominal pressure (IAP), spinal forces, load, and range of motion. Their findings are as follows:
- Belts increase IAP by approximately 20%.
- More IAP increases compression forces on the lower back. (as we know the risk of a low back injury increases with increased spinal compression).
- Electromyography (EMG) studies have found that back belts do not reduce muscle activation levels in the low back or abdominal muscles.
- Belts restrict range of motion in the lateral bend and axial twist axes, but have no effect on reducing flexion (which is the main motion associated with lifting tasks).
Physiological Studies
- Wearing belts increases blood pressure and heart rate.
Psychophysical Studies
- The load people are willing to lift increased by approximately 19% because belts give subjects a false sense of security .
Conclusions
Based on the above facts and data, following are my conclusions in regard to back belts.
- Do not universally administer back belts to all employees as a way to proactively address ergonomic risks in the workplace.
- Conduct a full ergonomic assessment of the workplace to identify the risks, develop potential solutions, and evaluate the effectiveness of solutions in mitigating the risks prior to issuing a back belt.
- To rule out potential complications associated with usage, screen potential back belt wears for cardiovascular risk (i.e., heart rate, blood pressure, etc.) prior to issuing a back belt.
- Provide back education training to all employees who wear belts. Emphasize both the importance of proper lifting techniques and the fact that belts do not enable you to lift more weight than you would without wearing one.
- Back belts are not designed for long term use. They may be beneficial in returning an injured employee to work, but emphasis must be placed on weaning employees off belts once injuries heal. (In this case, belts are considered a medical device, similar to a cast). Once the belts are removed, employees may need to condition themselves for a period of time to reduce the risk of injury.
If you would like to see the list of references on this subject or would like to see a specific topic covered in this column, email or give me a call.
Ergonomically Yours,
Ben Zavitz, CPE
EORM, Inc.
zavitzb@eorm.com.
tel: 781.938.9152 ext 106
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