In a previous post we outlined the 7 Biomechanical Ergonomic Risk Factors. Today we will explore the first risk factor: REPETITION.
Repetition is performing the same movements over and over again. Think of the typist, the checkout worker, or the meat worker. Repetition in itself is a risk factor, and it can also intensify exposure to other risk factors.
Why is repetition bad?
Not all repetitive tasks are bad – in fact a medium level of repetition is beneficial as it helps to strengthen tissue fibres and increase their flexibility. Doing a number of sets of the same exercise in gym is an example of good repetition. If, however, you move into the high rate of repetition, without adequate rest, the tissues are not able to recover and residual strain develops. If this level of repetition continues the tissues (such as tendons) will sustain multiple microtears from which they are unable to recover. The worker will begin to feel pain while completing their tasks and will start to use inefficient movement patterns to compensate. Eventually the tissue will fail and force the worker to stop and seek medical attention.
Clients often ask “why am I getting pain now, when I have been doing the same job for years?” This is a very good question, and is a very frustrating position for the worker to be in. One way to explain the phenomena is to think of the saying “the straw that broke the camels back” the continuous stress and strain on the tissues eventually weakens them to a point where they simply cannot continue.
How do I manage the risk of repetition?
Avoiding high rates of repetition is the best idea:
- Break up tasks throughout the day to avoid doing the same thing constantly
- Have a good understanding of the recovery cycles of your tissues – a trained Occupational Therapist can assist with this
- If the repetitive task also involves other ergonomic risk factors, such as force, then the amount of recovery time needed will increase
- Don’t ignore the first twinges of pain – these are your warning sign that the tissues are reaching their limit
Hope this helps explain repetition. If you are having difficulty managing we would recommend you seek the assistance of an Occupational Therapist trained in Ergonomics. They can complete a full worksite assessment with job task analysis to assist with reducing or removing the risk. Of course if your concern has resulted in hand or arm pain a Certified Hand Therapist will be able to help you.