Researcher Jim R. Potvin has proposed an equation that could have significant impact on the way ergonomists estimate risk for repetitive tasks. Potvin performed a meta-analysis of various psychophysical studies (e.g., Snook et al) that looked at the maximum acceptable efforts for a variety of tasks. He found that Duty Cycle, essentially the percentage of a job cycle that force or torque is exerted, can be used to predict maximum acceptable force and torque efforts.

Anthropometry is a primary consideration in ergonomics, yet is often misunderstood and misapplied in the design of equipment and systems. In this example of why ergonomics is not always "common sense," guest contributor Bruce Bradtmiller, a leading anthropometry expert, explains why it's important to understand the complexity of anthropometry, and provides an explanation of one technique called multivariate accommodation modeling (MAM) using principal component analysis (PCA). Sound complicated? Bradtmiller cuts through the complexity and provides a simplified understanding that will make you appreciate anthropometry in a new way next time you sit in a chair or glance into the cockpit of an airplane as you board. Creating a good fit is not as easy as some might think.