Ergonomic safety is big deal in the manufacturing world, where manual handling is a daily reality. But new guidelines from the Spine Research Institute suggest we need to be more conservative about how much is too much when it comes to pushing and pulling loads.
“Twenty percent of today’s back injuries relate to pushing and pulling. The cost of these injuries is increasing, while the cost of non-push/pull related activities is decreasing. So there’s a rationale for studying push/pull more in depth,” explained Gary Allread, program director of the Integrated Systems Engineering Group at Ohio State University. Allread was part of the team that developed the new guidelines, in cooperation with the Ohio Bureau of Workers Compensation.
According to Allread, current guidelines for pushing and pulling are flawed for a few reasons. One, they were developed using subjective methods that underestimate the risk of injury to the lower back and shoulders. And two, we’ve learned a lot about the impact that pushing and pulling has on the body over the last 20 years or so since the current guidelines were first developed.
“Our [new] guidelines are based on more objective and more sophisticated methods to understand what’s safe,” said Allread.
It turns out that how you’re moving something—pushing or pulling—plays a big role in your risk for injury. Allread and his team examined several key variables such as the way you hold your body (e.g. your posture) while moving, the straightness of the path you’re moving in, the height of the handle you’re using, and whether or not you’re employing one hand or two.
The body, Allread explained, can take compression very well when you’re lifting. But when you’re pushing and pulling a cart, for example, you’re moving your back in different ways. The safety risk is much greater because it’s putting stress on your spine that the body can’t tolerate.
Overall, the research concluded that objective, biomechanically-determined risk limits derived from the new study are up to 30% lower than the limits reported in current push/pull guidelines. It also provided the following recommendations:
- Higher handle heights (up to 48 inches) are generally preferable for all pushing and pulling exertions
- Turning push/pull exertions should be avoided when possible because they subject you to higher biomechanical loads
- Two-handed turning exertions (such as moving a cart) are recommended over one-handed turning exertions (such as moving a pallet jack)
Want an easy way to check if your next push/pull task is safe? Consult this free online tool.