Reliability of Safe Maximum Lifting Determinations of a Functional Capacity Evaluation

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. 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. 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. The ICC values for interrater reliability ranged from.95 to.98. Test-retest values ranged from.78 to.94. 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.