Using the wrong guidelines for push/pull?

June 25, 2019  |  Casters, Material Handling

It’s safe to say that most humans think they have a pretty good grasp on what their limits are, right? Well, not really. This is particularly evident in the workplace and with injury risk since musculoskeletal disorders, or MSDs, cause over $20 billion in direct costs each and every year, and this says nothing of the indirect costs. If workers and managers had a firm grasp on what each worker was capable of, they would take appropriate measures to prevent this injury. We can see how this applies across the board in all professions, as this study on wheelchairs and patient handling addresses. So, in this world of the internet, A.I., and self-driving cars, why are so many people still being injured?

In the specific case of push/pull, there are many reasons why people are still injuring themselves. However, there is one cause that should be changed immediately. Let’s say that company ergonomists and managers are diligently adhering to the only guidelines that are readily available for push/pull injury prevention. Injuries should be much less frequent than they currently are. However, the only guidelines for decades have been the Snook guidelines. Why is this a problem?

There are two main ways of determining push/pull guidelines. The first is psychophysical. This simply means that the guidelines are based on the opinions of the participants of the initial testing. In other words (within the Snook guidelines), the subjects pushed some weight and were asked if they could push or pull this much weight comfortably. The problem is that this is precisely the situation under which workers are still being injured.

The solution is to establish guidelines that are based on biomechanical testing. Biomechanical measurements have nothing to do with a test subject’s opinion. The only thing that scientists use is the data that a subject’s movements are producing. In this case, scientists can examine what a subject’s body is experiencing through digital imagery. If excessive weight is being placed on his or her spine, this shows up on the screen. Through testing participants, they can establish at what precise threshold, whether with movement or weight, the vast majority of subjects experience danger to their spine, etc.

guidelines for push/pull

The Ohio State University Spine Research Institute conducted a study that used these biomechanical criteria to establish much more reliable guidelines. The study concluded that these objectively determined guidelines were actually up to 30% lower than the subjectively (psychophysical) guidelines that have been the standard with the Snook tables for so long.

Caster Connection has now helped this same spine research institute to refine and go deeper into these results. This includes examining participant technique and the actual use of various gauges and transducers that a company might use to measure push/pull forces within its own facility but also how using the gauges themselves may skew results. The project is also examining exertion, acceleration, and rolling resistance. All of these details are based within the superior methodology of biomechanical assessment. The details of this project will not only keep your business moving along without downtime, but most importantly, it will help keep each individual in your company free from spine injury and debilitation.