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Ergonomics researchers from the University of Wisconsin-Milwaukee developed an approach for calculating the necessary time for safe lifting and lowering. Board-certified ergonomist Blake McGowan explain how their method quantifies the investment of forceful exertions and recovery time in this months installment.

References: Kapellusch J, Kapellusch JM, & Garg A. (2012). ERGONOMIC CYCLE TIME: A PROPOSED METRIC FOR THE DESIGN OF SAFE, PRODUCTIVE MANUFACTURING JOBS. Conference: 10th International Conference on Manufacturing Research, At Birmingham, England, Volume: Advances in Manufacturing Technology XXVI. September 2012.

Video Transcript

Hi, my name is Blake McGowan and I’m a certified professional ergonomist with a Humantech brand of VelocityEHS (now VelocityEHS Ergonomics).

One of the more difficult questions I get asked is: How do I justify the financial investment of implementing a manual materials handling intervention, such as a lift table or a hoist, when there really isn’t any history of injury? It’s unlikely to impact productivity and enhance any product quality, even though we have a higher risk of injury.

In 2012, Jacobellis and Arun Guard from the University of Wisconsin at Milwaukee developed a very simple but novel approach. Their approach calculates the necessary time for safe lifting based on the NIOSH lifting equation. There are two elements to that time: the performance time, as well as the necessary recovery time. They coined this the ergonomics cycle time.

If we compare the ergonomics cycle time to the process cycle time, which is currently the amount of time given to perform the task, we can determine if this is a safe lift. If the ergonomic cycle time is greater, we don’t have enough or the necessary recovery time, and now we’re at an elevated risk.

What we can do then with that necessary recovery time is convert that to a labor cost or an administrative cost. This is the cost or investment that you’re making in that forceful exertion, as well as the recovery time. We can then compare that to the cost of an engineering control, such as the lift table or hoist, and determine which is the most cost-effective approach.

So, what does this mean? What’s the bottom line?

The bottom line is that forceful exertions relate to effort. Effort equals recovery time. Recovery time is related to cost. If we can actually lower that recovery time by implementing a lift table or a hoist, we can perform this task safely and meet that process cycle time.

So, for more information on Humantech and the Bottom-line series please feel free to visit our website at Humantech (

Thanks, have a great day.