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Technology innovations of Saturn Ergonomics are rapidly getting noticed in the ergonomics community. Evaluation models authored or co-authored by Murray Gibson have been included in panel discussions at international ergonomics conferences.


  • AEC (Applied Ergonomics Conf.), 2019 - New Orleans, LA

  • IEA (International Ergonomics Assoc.), 2018 - Florence Italy

  • ACE (Assoc. of Canadian Ergonomists), 2017 - Banff, Alberta Canada).

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Saturn Ergonomics uses modern, state of the art ergonomics evaluation models including:


  • RCRA, Recommended Cumulative Recovery Allowance (Gibson & Potvin, 2016), is a versatile multi-task force evaluation model derived from the Potvin MAE Equation (Potvin, 2012).

  • MAEIS, Maximum Acceptable Effort for an Isolated Subtask (Gibson & Potvin, 2017), is a multi-task model used to determine the acceptable force limit for one force, given similar (but different) forces occurring during the same work cycle.

  • Fatigue-Failure is a family of ergonomics evaluation models developed by Auburn University. These multi-task models predict injury risk levels based upon lifting (LiFFT™, Gallagher et al, 2017), distal upper extremity forces (DUET™, Gallagher et al, 2018), and shoulder force (The Shoulder Tool™, © Dania Bani Hani et al, 2019). 

Saturn Ergonomics’ provides the training, knowhow, and support technologies necessary to effectively apply these new ergonomics evaluation technologies. 

Single-task Limitations:

Most ergonomic evaluation models and risk assessment tools are single-task models. Single-task models assume that the exposure levels of force, posture, and repetition/duration are constant (i.e., the worker does the same thing every time).

But in real jobs, workers don’t do the same thing every time! The force required to complete one step of a job may be greater, or less, than forces required to complete other steps. And some forces require more time to complete than other forces. Real work is multi-task; people do different things. Exposure level and duration of forces and awkward postures often differ over the work cycle.

When applying a single-task evaluation or risk assessment model, the practitioner is presented with a difficult decision; What exposure level to use? There are two conventional approaches. One is to use the average exposure level. The other is to take the conservative route and use the worst case exposure level.

But neither approach truly represents the variation in physical exposures (force, posture, and repetition/duration) experienced by the worker. Using the average exposure understates the problem, and using the worst case exposure overstates it.

Saturn Ergonomics relies upon modern multi-task ergonomic evaluation technologies. These new multi-task models overcome these single-task model limitations. 

Using these new multi-task ergo evaluation models, it’s possible to evaluate different levels of force, posture, and repetition/duration… in a single calculation! And these new models provide other advantages.

Multi-task Advantages:

Multi-task ergonomics evaluation models enable us to:


  • Calculate cumulative exposure metrics when employees rotate into different jobs/stations over the shif

  • Establish daily exposure limits for time spent working at an individual job/station, or combinations of jobs/stations.

  • Demonstrate the benefit of small, incremental improvements.

  • Simulate how changes to operational metrics such as cycle time, shift duration, and overtime will impact ergo-related metrics.


And multi-task ergo evaluation models provide higher “analysis resolution”, enabling us to see what needs to be fixed!

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More insightful analysis leads to more effective solutions! 

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