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Which jobs are the most concerning from an ergonomics standpoint? VelocityEHS’ Blake McGowan will show you what to look for as he explains the four key ergonomic risk factors and how they interact.

Video Transcript

Hello, I’m Blake McGowan from Humantech (now VelocityEHS Ergonomics), and I’m a certified professional ergonomist. Today, I’d like to talk a little bit about ergonomic risk factors. There are three primary ergonomic risk factors: high force, awkward posture, and high repetition. Many people assume that each of these three risk factors are equally related and don’t interact with each other. Unfortunately, research has shown this is not true. Some of these are weighted differently, and there are definitely some types of interactions between each of these risk factors.

Sean Gallagher did an excellent study in 2012 that showed these types of interactions. They occur at different joints throughout the body and for many different disorders. Let’s go take a look at that data. Here’s the graph that illustrates that interaction. On the vertical axis, we have the risk of injury, and on the horizontal axis, we have two categories: the first one being low repetition and the second one being high repetition.

When we start to look at the influence or interaction with repetition and force, we see two different patterns. For example, here, when we have a low force situation and we perform that in low repetition, our risk of injury is fairly low. As we then transition to a higher repetition situation, still at low force, our risk of injury is about the same. Now, things really start to change when we look at high force. In a high force situation in low repetition, we still have a fairly low risk of injury, but it really starts to escalate when we transition to a high force situation in high repetition.

So, we have this force-repetition interaction. One other thing that we have to consider here is that third risk factor, posture. We know that in awkward postures, it’s going to influence our force profile. So, we can easily remove force here and put in awkward posture or neutral posture, and the relationship would be the same. So, really the takeaway from this research is that we should really focus on high force, as well as awkward posture situations, that occur at high repetitions. That’s where we’re going to get the most value out of our efforts.

If you’re interested in more information on this, please visit our website at Humantech (now We’d be happy to have you.