Affiliations: X-RTS Software Products and Testing Devices, Hopedale, IL, USA | Millikin University, Decatur, IL, USA | WCS Occupational Rehabilitation Sports Medicine, Palos
Heights, IL, USA | WorkSTEPS, Austin, TX, USA
Note: [] Address for correspondence: Darrell Schapmire, MS, X-RTS
Software Products, Inc., P.O. Box 171, Hopedale, IL 61747, USA. Tel.: +1 309
449 5483; E-mail: ds@xrts.com
Abstract: Objective: The objective was to determine if visual estimation of
effort (VEE) during lifting tasks is accurate in classifying relative levels of
exertion or distinguishing between incomplete lifts that may be potentially
unsafe and incomplete lifts of "actors" feigning weakness. Participants: A convenience sample of 117 health professionals and lay
subjects participated in the study. Methods: Four actors were videoed
performing four complete dynamic lifts (sets of five repetitions) of varying
levels of exertion (relative to subjects' physical maximum). Subjects viewed
the videoed performances, presented in no apparent order, attempting to
properly classify the lifting tasks. For the four levels of exertion,
participants were to judge if the lifts were 25%, 50%, 75% and 100%
of each actor's maximum lifting capacity and to distinguish between an
incomplete (failed) lift of 110% of maximum and a feigned failure of a lift
of 25% of maximum. Results: Accuracy for in classifying all lifting
activities was marginally higher than chance. There were no differences in the
accuracy of health professionals or lay subjects. Conclusion: The VEE does not accurately classify relative levels of exertion or distinguish between
incomplete feigned effort lifts and lifts that are potentially too heavy to safely lift.
