According to the Bureau of Labor Statistics, musculoskeletal disorders (MSDs) made up approximately one-third of all lost workday cases in 2001. While office workers may receive the most attention in the popular press, the manufacturing and services industries had the highest numbers of MSDs in 2001. In addition, BLS reported that among frequent events or exposures, repetitive motion injuries resulted in the longest absences from work about 18 days.
So what exactly are MSDs? They are conditions that affect the nerves, tendons, muscles and supporting structures of the body such as invertebral discs. Usually they are caused by prolonged or repeated exertion of one part of the body, such as frequent heavy lifting, maintaining an awkward posture for a long period of time or even vibration. MSDs can include painful and debilitating conditions such as:
- Carpal tunnel syndrome Caused by pressure to the median nerve that runs through the carpal tunnel (which is made up of ligaments and bones).
- DeQuervain's tenosynovitis Swelling and inflammation of the tendons and tendon sheath on the thumb side of the wrist.
- Tennis Elbow, or Lateral Epicondylitis Caused by tears in the muscles or tendons that are attached to the outside bony part of the elbow.
- Low Back Pain
- Hand-Arm Vibration Syndrome (HAVS) Caused by the vibration of power tools that leads to numbness of the hand.
For those in the industrial field, a number of workplace applications can cause these disorders. Power tools used by construction workers chainsaws, sanders, grinders and jackhammers, for example can cause vibration injuries. The repeated heavy lifting involved in the retail and the material handling industries can cause lower back pain.
While the Occupational Safety and Health Administration (OSHA) has not yet produced a single standard related to preventing ergonomic injuries, it has developed guidelines for specific industries such as nursing homes, poultry processing and grocery retailers. For industries that do not yet have guidelines, they should assess the potential ergonomic hazards in the workplace and develop a program to address them.
When developing an ergonomics program, the National Institute for Occupational Safety and Health (NIOSH) recommends reducing or eliminating potentially hazardous conditions by using engineering controls (i.e., using machines to transport materials); changing work practices and management policies (i.e., reducing length of shifts or rotating workers through jobs with different physical demands); and using personal protective equipment.
It is the final recommendation of using personal protective equipment that this article will explore.
A study published in 2002 in the International Journal of Occupational and Environmental Health found that those who wear back supports had an average of 15 percent fewer acute back injuries than those given only lifting advice, and 26 percent fewer acute back injuries than those with neither lifting advice nor back support belts. The study was conducted among 12,700 home attendants in New York City.
In choosing the correct back support, there are a number of qualities you may want to consider. First, take a look at the number of stays, or supports, that line the back support belt. Generally, the more stays in a belt, the better the protection. They provide stability and support to the spine. Stays can be made from plastic or metals such as aluminum, but spring steel stays are the best at providing flexibility and strength. They conform to body shapes and spring back to their original form when not engaged, whereas some other materials may remain bent.
Metal stays should have plastic coating on the ends to prevent them from poking through the pockets that keep them in place. In addition, look for stay pockets that feature a rubber lining that will grip clothing and prevent the back belt from sliding out of place.
Many back belt supports are made with shoulder straps that help keep the belt in place when it is unfastened. They should be elastic and adjustable so that they do not hang loose on a worker. Break-away shoulder straps are an added safety feature for those who work near machinery, lowering the risk of entanglement in moving parts.
Another feature to consider is the material used to fasten the belt together. Be sure to choose a closure system that is secure and won't break apart under stress.
Also key when choosing the right back support belt is ensuring that it fits properly. Employees should be measured at both the waist and the hip. Waist measurements should be made around the widest portion of the waist below the navel with the clothes on. Hip measurements should be made about 2 inches below the navel. Those two measurements will help you determine which size will best fit your employees.
According to Kent Wilson, director of Ergonomics for the Ergodyne Corp., good back supports should also have a two-stage closure system. One closure secures the support around the waist and positions the stays while the second engages the side panels to form the stays to the back once the support is in position. Wilson recommends back supports be worn loose and just below the navel.
"How long an employee should wear a back support may depend on the nature of his or her job," said Wilson. "If an employee will be lifting materials throughout the day, it might be a good idea to wear the back support continuously but in a relaxed position when lifting is not required. That way, you have it ready to be engaged at any time as opposed to taking it off and then forgetting to use it."
Wrist supports can be useful in preventing conditions such as carpal tunnel syndrome, which can be caused by repetitive strain on the wrist. These supports work like external ligaments to help keep the wrist in a neutral position and limit the flexion (downward movement) and extension of the wrist, while allowing for full finger movement.
For preventive purposes, Wilson noted, it is important to avoid a wrist support that is too stiff or rigid.
"You want to avoid those qualities unless it's prescribed by a doctor," he said. "You want to be sure you are not restricting your employee's range of motion."
In examining the type of material the wrist support is made from, consider the durability, flexibility and breathability of the fabric. For example, an employee involved in lots of lifting might need a durable wrist support that will maintain its protective qualities throughout multiple uses. Having a breathable fabric or a liner that prevents perspiration build-up might also be important in selecting a wrist support for such an employee.
Thumb loops can be helpful in keeping the wrist support in the right place. Also examine the type of closure on the wrist support. Choose a more durable type of closure, such as Velcro, for heavier jobs. Hook-and-loop closures are a bit less durable and might be more suitable for less strenuous activities.
"The last thing you want an employee to do is keep fiddling with the closures. It can become a distraction and then a safety issue," Wilson noted. "You want something that will stay closed and also be adjustable. Adjustability is key."
Gloves that can reduce the vibration from power tools were once thought to be inefficient in that they were too bulky to allow for easy movement. But with the development of materials such as Lycra and Spandex, dexterity no longer has to be sacrificed for protection. Vibration-reducing gloves usually feature pads that cover the palm, web and thumb to absorb impact. The pads can be made from viscoelastic material, composite materials such as Gelfom, gels or polymers.
Last year, the American National Standards Institute (ANSI) adopted a European glove standard to determine vibration attenuation in gloves. The new standard, ISO 10819, divides the vibration spectrum into medium- and high-frequency ranges. To be ANSI-compliant, gloves must not augment vibration in the medium range and must reduce vibration in the high range by approximately 40 percent.
Wilson said employers should be aware of the difference between vibration and impact when choosing the appropriate glove. Employees are at risk for vibration injuries when they use a tool that is powered by an external power supply, such as a jackhammer or drill. Workers are at risk for impact injuries when the tool is powered by hand, such as a hammer.
Only full-finger gloves can meet the ANSI standard, Wilson noted. They provide protection for the fingertips and palms, and are best used in applications in which the employee is at risk for vibration. Half-finger gloves, Wilson noted, should be used to protect against impact caused by hammering, using a screwdriver or hand-sanding. Also, if an employee uses his or her hand as a hammer, half-fingered gloves can help absorb and dissipate shock in the palm, web and thumb areas of the hand while leaving the fingers exposed to guide tools.
Elbow supports help redirect strain and vibration away from the elbow and reduce the chance for developing lateral epicondylitis, or tennis elbow. The supports, in essence, fool the body into thinking that the forearm muscle that attaches to the tendon at the elbow actually attaches below the elbow. This moves the stress away from the elbow to the belly of the muscle, according to Wilson.
"It's important to place the strap appropriately," Wilson said. "As a rule of thumb, it should be placed two to three finger-widths below the crease of the elbow so that the area above it has the ability to rest."
Knee Supports and Pads
According to NIOSH, carpet layers, tile setters and floor layers are at particular risk for knee injuries caused by frequent kneeling. For carpet layers, the use of a knee kicker to stretch carpet wall-to-wall is also a danger.
In professions such as these, knee pads are a must. According to NIOSH, they can help distribute body weight over a wider area while also eliminating the potential for puncture wounds.
When choosing the right knee pad, consider what type of surface your employees will be working on. For those who work on smooth surfaces, a knee pad with an outer shell that has treads is useful for preventing slips. Knee pads with smooth outer shells to protect the kneecap are better suited for those who kneel on carpeting.
Some knee pads are constructed with a hinge so that they bend with the knee. Such pads are excellent for those who kneel and stand repeatedly, eliminating the restricted movement that can come when the knee pad is worn in the standing position.
Common sense also comes in to play when preventing knee injuries. Allow employees to take frequent breaks to stretch their legs and alleviate the strain on their knees. NIOSH also recommends that carpet layers replace the use of knee kickers with power stretchers, which are hand-arm operated devices.
Get started on an ergonomics program that includes PPE. As awareness about MSDs grow, hopefully these products will become more and more common in the workplace. Be sure to make them a part of your safety program today.
Julie Copeland is vice president of sales for Arbill Industries, which includes Arbill Industrial Laundry and Arbill Safety Products. Arbill Safety Products is a national supplier and manufacturer of safety products and services, and is located at 10450 Drummond Road, Philadelphia, Pa. 19154. One of the top 100 industrial distributors in North America, Arbill is both ISO 9002 and ISO 14001 certified. For more information, visit Arbill at www.arbill.com, or call (800) 523-5367.