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Apr 29, 2018

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7 Ways to Prevent Ergonomic Injuries

What is an ergonomic injury?

Opinions vary on how to define an ergonomics injury, and the definition of the term may depend on the context. However, ergonomic injuries are often described by the term “musculoskeletal disorders” or “MSDs.” This is the term that refers collectively to a group of injuries and illnesses that affect the musculoskeletal system.

Musculoskeletal disorders (MSDs) include a group of conditions that involve the nerves, tendons, muscles, and supporting structures (such as intervertebral discs). They represent a wide range of disorders, which can differ in severity from mild periodic conditions to those which are severe, chronic and debilitating. Some musculoskeletal disorders have specific diagnostic criteria and clear pathological mechanisms (like hand/arm vibration syndrome). Others are defined primarily by the location of pain and have a more variable or less clearly defined pathophysiology (like back disorders). Musculoskeletal disorders of the upper extremities include carpal tunnel syndrome, wrist tendonitis, epicondylitis, and rotator cuff tendonitis. Both non-occupational and occupational factors contribute to the development and exacerbation of these disorders.

  • Carpal tunnel syndrome,
  • Tendinitis,
  • Rotator cuff injuries (affects the shoulder),
  • Epicondylitis (affects the elbow),
  • Trigger finger, and
  • Muscle strains and low back injuries.

There is no single diagnosis for MSDs.

As OSHA continues to develop ergonomics-related guidance material for specific industries, the agency may narrow the definition as appropriate to address the specific workplace hazards covered. OSHA says it will work closely with stakeholders to develop definitions for MSDs as part of its overall effort to develop guidance materials.

Musculoskeletal disorders

Lower back disorders
The research into MSDs supports a relationship between the development of lower back disorders and each of the following workplace risk factors:

1. lifting and forceful movements,
2. bending and twisting in awkward postures, and
3. whole-body vibration.

Disorders of the neck and shoulders
For disorders of the neck and neck/shoulder region, the research identifies two important workplace factors:

  1. sustained postures causing static contractions of the neck and shoulder muscles (for example, working overhead in automobile assembly or in construction), and
  2. combinations of highly repetitive and forceful work involving the arm and hand, which also affect the musculature of the shoulder and neck region.

Disorders of the hand, wrist, and elbow

There are several conditions to consider within the hand and wrist region. Combined work factors of forceful and repetitive use of the hands and wrists are associated with carpal tunnel syndrome. Vibration from hand tools like chainsaws (those that do not have vibration controlling mechanisms) also contributes to carpal tunnel syndrome.

Vibrating tool use has also been strongly linked to hand and arm vibration syndrome, a separate condition of the hand and wrist that affects the nerve and blood vessels.

Carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a cumulative trauma disorder (CTD) affecting the hands and wrists. CTS is the compression and entrapment of the median nerve where it passes through the wrist into the hand in the carpal tunnel.

The median nerve is the main nerve that extends down the arm to the hand and provides the sense of touch in the thumb, index finger, middle finger, and half of the fourth, or ring, finger.

When irritated, tendons housed inside the narrow carpal tunnel swell and press against the nearby median nerve. The pressure causes tingling, numbness, or severe pain in the wrist and hand. The pain is often experienced at night. The pressure also results in a lack of strength in the hand and an inability to make a fist, hold objects, or perform other manual tasks. If the pressure continues, it can damage the nerve, causing permanent loss of sensation and even partial paralysis.

CTS develops in the hands and wrists when repetitive or forceful manual tasks are performed over a period of time. For example, the meatpacking industry is considered one of the most hazardous industries in the United States because workers can make as many as 10,000 repetitive motions per day in assembly line processes, such as deboning meats, with no variation in motion Consequently, stress and strain placed on the wrists and hands often results in CTS.

Today, more than half of all U.S. workers are susceptible to developing CTS. Anyone whose job demands a lot of repetitive wrists, hand, and arm motion, which need not always be forceful or strenuous, might be a potential victim of CTS. CTS is common among meat and poultry workers, letter sorters, carpenters, garment workers, upholstery workers, shoe and boot makers, electronic and other assemblers, packers, product inspectors, machine operators, computer/keyboard operators, and cashiers.

Since the early 1980s, CTS has been reported widely among many service-sector employees, including office workers and newspaper and news service employees who use video display terminals (VDTs). CTS, among other health effects, is becoming a growing problem among VDT users because of the numerous repetitive motions of keystroking data into the computer over long periods.

Compounding problems is the fact that employees are often unaware of the causes of CTS and what to do about them. Initially, the person may have fatigue and pain that develops during the workday and disappears overnight with no physical symptoms. After a length of time, fatigue and pain develop earlier in the day, some physical symptoms such as clumsiness may occur, which affect work performance, and there may be no overnight recovery. When the case becomes full-blown, there is constant fatigue and pain with no overnight recovery, and disturbed sleep results.

At this point, work performance is inhibited to the extent of requiring off-duty time or light/restricted duty. Often victims do not associate their pain with their work because symptoms may only occur during evening or off-duty hours. When workers finally seek medical help, they may be given the wrong diagnosis and find the road to recovery takes more time and money than had been anticipated.

Length and intensity of exposure

The research indicates that the greater the level of exposure to a single risk factor or combination of factors, the greater the risk of having a work-related musculoskeletal disorder. An additional important factor is a time between each episode of exposure. With adequate time to recover or adapt, and particularly when lower forces are involved, there may be less harm done to the body from repeated exposures. The intensity, as well as the extended length of the exposure to forceful, repetitive work, plays a substantial role in the risk of work-related musculoskeletal disorder in many traditional occupational settings.

What factors may contribute to symptoms of MSDs?

Each person has physical limits or a “comfort zone” of activities and work levels they can tolerate without developing symptoms of musculoskeletal disorders (MSDs). Some factors which may contribute to MSD symptoms include:

  • Furniture designs or a work area arrangement which produces bad postures.
  • Physically demanding work which employees are not accustomed to.
  • Workers who are generally out of shape.
  • Underlying arthritis.
  • Diminished muscle strength or joint flexibility.

What’s a good plan for preventing work-related musculoskeletal disorders?

A good plan starts with employee involvement. Employers and employees can work together effectively to reduce work-related musculoskeletal disorders (WMSDs). Here are some ways:

  1. Look at injury and illness records to find jobs where problems have occurred.
  2. Talk with workers to identify specific tasks that contribute to pain and lost workdays.
  3. Ask workers what changes they think will make a difference.
  4. Encourage workers to report WMSD symptoms and establish a medical management system to detect problems early.
  5. Find ways to reduce repeated motions, forceful hand exertions, prolonged bending, or working above shoulder height.
  6. Reduce or eliminate vibration and sharp edges or handles that dig into the skin.
  7. Rely on equipment (not backs) for heavy or repetitive lifting.
    Simple solutions often work best. Workplace changes to reduce pain and cut the risk of disability need not cost a fortune. For example:
  • Change the height or orientation of the product or use tools with handles designed so that workers won’t have to bend their wrists unnaturally to use the tool.
  • Offer workers involved in intensive keyboarding more frequent short breaks to rest muscles.
  • Vary tasks of assembly line workers to avoid repeated stress for the same muscles.
  • Provide lifting equipment so workers won’t strain their backs.
  • Lifting equipment is available for everything from boxes and crates to nursing home patients.

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