Repetitive Motion Injury

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To Your Health -- CHRC Newsletter

Summer 1999

by Debbie Swartz, R.N., PAMF Ergonomics Educator

We are usually not conscious of all the individual parts of our body when they work in synchrony. Most of us go through our activities of daily living without thinking about the impact these activities may have on our body. As a result some of us experience a repetitive motion injury, or cumulative trauma disorder.

Repetitive motion injuries are wear-and-tear injuries that occur because of repetitive activities that we perform at work and at home. These injuries are due to repeated strain to muscles, tendons and joints in the hands, wrists, elbows, shoulders, back and neck. At first, the symptoms may be intermittent and we may ignore them. But in time, they become constant and require attention.

SYMPTOMS

Repetitive motion injury symptoms include:

• fatigue in muscles and joints
• aches and pains
• swelling


• tightness/stiffness (especially over joint areas)
• tingling or numbness


• weakness.

If you notice these symptoms occurring intermittently, you should consider the possible causes and make changes in your use of repetitive motion in performing activities. If symptoms become persistent or cause you to wake up in the night, you should seek medical help.

CAUSES

Activities at work that can lead to injury are those that are repetitive in nature, such as using the same hand and arm in performing the same work tasks for prolonged periods of time; or holding your hand and arm in awkward positions that put strain on nerves, muscles and tendons. Some examples are: data entry; typing reports; painting; stapling/hole punching; hammering; cradling the phone under your chin; and filing.

Activities performed at home that can lead to repetitive motion injuries include: computer work; hobbies such as knitting, sewing and woodwork; playing a musical instrument; gardening; sports such as tennis, golf and racquetball; and household chores such as cooking, laundry and cleaning.

There are factors that can increase the risk of developing a repetitive motion injury. Being aware of these risk factors can assist you in changing the way you perform certain activities and preventing injuries from occurring.

• Repetitive motion: when a task is repeated frequently it can cause strains and fatigue in muscles, joints and tendons.


• Forceful exertion: tasks that require force place a higher load or stress on muscles, tendons and joints.


• Awkward posture/position: poor posture while performing a task, especially a repetitive task, puts strain on joints and muscles.


• Duration: tasks that require the use of the same muscles for long periods of time can cause fatigue in those muscles and make them susceptible to injury.


• Compression: pressing body parts on hard or sharp surfaces causes a decrease in blood flow to the muscles, tendons and nerves in that area. This can cause symptoms of tingling, numbness and change in sensation, and lead to tissue damage in that area.


• Vibration: activities involving vibration put stress on individual parts or the whole body.


• Poor physical health: conditions such as diabetes, cardiovascular disease, Raynaud's, arthritis, smoking, alcoholism, gout, hypertension, poor nutrition, lack of exercise, stress and job dissatisfaction can increase the chance of developing a repetitive motion injury.

Children, too, can be at risk for developing these injuries. They often sit for long periods of time at computers, using the keyboard and mouse for school projects as well as recreation. It is important for them to have a work area at home that minimizes their risk for developing an injury. They should have an appropriate-sized chair that supports the lower back and is adjusted so that the child can be at the correct height for using the keyboard. They should be able to work at the computer with relaxed shoulders, and wrists in a neutral, flat position. Writing for long periods frequently can cause strain on the hand and forearm. Using a wide grip pen or pencil can help reduce this strain. Children should also be advised to take frequent stretch breaks while at work for more than an hour. Fortunately, most children have a variety of tasks and interests, so the repetitiveness and duration of tasks may not be as high a risk factor as it is for adults.

Also, children carry heavy backpacks to and from and during school. This can cause strain on their backs, with the potential for an acute as well as a repetitive strain injury. Many schools and parent groups are working to resolve this problem. Until a solution has been found, the following may provide some relief: advise the child to carry the backpack by sharing the load between the back and arms, or using a portable luggage carrier they can push (not pull).

PREVENTION OF REPETITIVE MOTION INJURY

It is important to decrease the amount of continuous time spent performing repetitive activities that can lead to injury. This can be done by:

1. Taking a break from sitting at work by getting up every hour.
2. Taking a "stretch break" every 20 to 30 minutes for 1 to 2 minutes. Stretching the tendons and muscles can help reduce your risk of injury.


3. Here are some stretches you can try:
   • Finger stretches--Open your hand and spread your fingers, then close your hand. Repeat this three times.
   
   
   • Arm dangles--Dangle your arms down by your sides in either standing or sitting positions.
   
   
   • Chair-back stretches--Lace your hands behind your head and carefully lean back over your chair backrest to stretch the front of your chest.
   
   
   • Back extension--While standing, put your hands on your hips and gently lean backwards.
   
   
   • Shoulder rolls--Roll your shoulders up and backwards and move your elbows with your shoulders to increase the effect of the stretch.
   
   
   • Ear-to-shoulder--Drop your head to the side so your ear moves toward your shoulder. Repeat in other direction.


4. Vary or rotate the tasks you perform during the course of the day.

There are also general guidelines for your workspace:

• Adjust your workstation and chair so the keyboard is just below your hands when your shoulders are relaxed, elbows at 90 degrees and arms/wrists are flat.


• Maintain proper posture.
• Take care of yourself--eat well, exercise and get enough sleep.


• Pay attention to symptoms early.

Being aware of risk factors as causes of repetitive motion injury is the first step. Changing your work or home environment to reduce these risk factors is a priority, especially when symptoms are present and intermittent. We often take for granted that all of our joints, nerves, muscles and tendons will work when we need them to. It is important not to overlook the long-term effects of stress and strain on joints, nerves, muscles and tendons that can lead to injury.