Affiliations: WCS Occupational Rehabilitation Sports Medicine,
Naperville, IL, USA | X-RTS Software Products, Inc., Hopedale, IL, USA | Millikin University, Decatur, 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 purpose of this study was to determine if these two
commonly-administered isometric tests are accurate indices of effort. Participants: 34 healthy subjects were tested once giving a maximum voluntary
effort and once attempting to feign weakness of 50% of maximum. Results: During feigned weakness sessions, 20 of 34 subjects (58.5%),
produced CVs of 15% or less during the Leg Lift. At the 95% CI, the
expected frequency of false negatives for feigned weakness is 42.3 to 75.3%
for the Leg Lift. At the 95% CI, the expected frequency of false negatives
for feigned weakness is 51.9% to 83.3% for the Arm Lift. Conclusions: Neither isometric lift is appropriate for classifying validity of
effort. Use of these isometric lifts should be discontinued for the assessment
of effort.
