Reliability of safe maximum lifting determinations of a functional capacity evaluation

Background and Purpose. Functional capacity evaluations (FCEs) are measurement tools used in predicting readiness to return to work following injury. The interrater and test-retest reliability of determinations of maximal safe lifting during kinesiophysical FCEs were examined in a sample of people who were off work and receiving workers' compensation. Subjects. Twenty-eight subjects with low back pain who had plateaued with treatment were enrolled. Five occupational therapists, trained and experienced in kinesiophysical methods, conducted testing. Methods. A repeated-measures design was used, with raters testing subjects simultaneously, yet independently. Subjects were rated on 2 occasions, separated by 2 to 4 days. Analyses included intraclass correlation coefficients (ICCs) and 95% confidence intervals. Results. The ICC values for interrater reliability ranged from .95 to .98. Test-retest values ranged from .78 to .94. Discussion and Conclusion. Inconsistencies in subjects' performance across sessions were the greatest source of FCE measurement variability. Overall, however, test-retest reliability was good and interrater reliability was excellent.