Health and Safety

Occupational Overuse Syndrome (OOS)

What Is OOS?

Occupational Overuse Syndrome (OOS) is the term for several conditions which cause discomfort in muscles, tendons, and other soft tissues. The symptoms can include:

  • Fatigue
  • Muscle discomfort
  • Burning
  • Aches and pains
  • Soreness
  • Numbness and tingling

What Causes OOS?

OOS often develops over a period of time. It is usually caused, or worsened, by particular types of work. Repeated movements, sitting in the same position, or in cramped positions, for long periods, and forceful movements are usually involved. Stress can be a factor, too.

One theory is that OOS is caused by muscles being tensed for too long. Muscles and tendons can recover from fatigue if tasks are varied and you take regular rest breaks. Muscles and tendons may be strained beyond their ability to recover if you work without varying your tasks or taking rest breaks.

How Can I Prevent OOS?

Whenever you are using a computer you should remember:

  • Posture
  • Relaxation
  • Micropauses


1) Relax Your Shoulders

Keep your shoulders low and relaxed. To find out how it feels - shrug your shoulders. Raise them as high as possible, then let them fall - straight down, not forward. Get used to how it feels when your shoulders are low and relaxed.

Try to have your shoulders relaxed whenever you sit down at a computer bench.

2) Let Your Elbows Swing Free

The best posture for your elbows is when they hang loosely below your shoulders. To find this position, concentrate on your elbows swinging.

3) Keep Your Wrists Straight

Holding your wrists angled upwards, downwards, or sideways requires muscle tension which can cause fatigue and lead to OOS.

4) Pull Your Chin in to Look Down

To look down, pull your chin in so that your neck muscles are not tensed. Looking down by rotating your eyeballs is also better than leaning forward.

5) Keep the Hollow in the Base of Your Spine

Sitting often causes poor posture in the base of your spine and can lead to back pain. It is important to keep the hollow in the small of your back. Make sure the small of your back is well supported by the back rest of your chair.

6) Try Leaning Back in Your Chair

There's a difference between leaning back and slouching! Leaning back will help you keep the hollow at the base of your spine as long as you have a backrest that supports you in the small of your back.

7) Don't Slouch or Slump Forward!

8) Change Your Sitting Position Often

Muscles are meant to move. You can get tense staying in the same position.

9) Adjust Your Chair Height Correctly

Your thighs should be level with the floor, your knees and ankles should not be bent into tight angles, and your feet should be well supported.



A micropause is a very short break for relaxation - five to ten seconds taken every three to five minutes. Your muscles should be fully relaxed, otherwise a micropause will be of no value to you.

Micropauses allow for restored blood flow in muscles that have been tensed. Try to make them a natural part of your routine when using a computer.