If you type on a keyboard, pipette, or do anything repetitive with your hands for a long time, chances are you’ve felt it: numbness in the base of the thumb, pain in the wrist, or a weak feeling in your hand. These sensations can come from a lot of things, but the symptoms add up to repetitive strain injury (RSI).
With the word repetitive in its name, it’s no surprise that pipetting— the most repetitive part of your job— causes RSI. In this article, we’ll share with you what RSI is, what causes it, and how you can prevent your daily pipetting activities from causing it.
What is Repetitive Strain Injury?
RSI is an inflammatory reaction to stress on a joint or limb, where key nerves have rubbed against bone and other structures in the joint. Examples of RSI range from tendonitis of the hand to carpal tunnel syndrome in the wrist to cubital tunnel syndrome in the elbow. Symptoms can arise long after you finished pipetting and can also last a long time. These symptoms also are not limited to your wrist or hand—most injuries reported extend into the back and shoulders.
How Pipetting Causes Repetitive Strain Injury
Two main physical issues contribute to RSI: force and repetitiveness. Force in pipetting comes from dispensing the contents, ejecting the pipette tip, and keeping a tight grip on a poorly designed pipette.
And pipetting is usually very repetitive, as any laboratory worker knows too well. A single person might go through pipetting motions thousands of times in one day. If you’re pipetting for more than four hours a day (and many lab scientists do), you’re at risk for RSI.
Use Proper Pipetting Technique to Prevent RSI
Fortunately, RSI is preventable, and often treatable. Here are some suggestions to help it from manifesting for you:
Use Your Body Correctly
Correct technique, habits, and posture will go a long way to reduce the force and repetitiveness of pipetting and other lab activities:
- Avoid keeping your arms extended or elevated for prolong periods of time. Raise your chair instead of reaching out to pipette. When pipetting, keep your elbow angle at a 90 degree angle with your hands straight out. This minimizes the exertion needed to do your work and can prevent strain on your nerves, muscles and tendons.
- Your posture will also help prevent RSI. Sit or stand up straight, with shoulders slightly back and lined up with your ears. If sitting, your back should be against the backrest of your chair. If standing, shift your pelvis forward so it is aligned over your ankles.
- Take a break! Take breaks often, in fact. The Occupational Health and Safety Administration (OSHA) recommends taking a two minute break every 20 minutes. Be sure to stretch your hands, arms, and shoulders frequently.
Use Ergonomic Pipette Supplies and Equipment
While there’s not much you can do about the repetitive part of pipetting, there are specific products designed to reduce the force of pipetting. Force comes into play when you’re attaching the tip to the pipette, aspirating and dispensing liquid contents, and ejecting the tip.
Tip mounting requires the most force and, therefore, is most likely to contribute to injury. You should not have to twist your wrist or pound the tip into the end of pipette to get a good fit—all these motions can eventually lead to repetitive strain.
A tip with a flexible proximal end will reduce these motions and the mounting force. The flexible end forms a secure seal with the pipette barrel, so there no banging or rocking necessary.
Tip ejection necessitates the second most energy. The ejector button is often located next to the plunger at the top of the pipette, requiring you to move your thumb an awkward half step over and push down. This awkward movement contributes to RSI in the thumb.
Pipette companies have taken RSI seriously and now offer pipettes with low-profile ejector button placement. Some pipettes even have adjustable ejector buttons for left-and right-handed users. All of these adjustments reduce the ejection force.
But just as important are the tips themselves. Tips that are a good fit for your pipette will attach and detach smoothly from your pipette with minimal force, minimizing any RSI risk, not to mention giving you more accurate results.
Listen to Your Body
Keep in mind that any continued pain or discomfort should be evaluated by a medical professional. In some cases, physical therapy or other medical intervention may be necessary. RSI has many causes, and there are many ways to treat it. But reducing the risks of pipetting with the right posture and equipment can go a long way to preventing pain.
Image Credit: Maggie Bartlett, NHGRI