The Progressive Isoinertial Lifting Evaluation (PILE) and the lifting test of the WorkWell Systems Functional Capacity Evaluation (WWS) are well known as lifting performance tests. The objective of this study was to study whether the PILE and the WWS can be used interchangeably in patients with Chronic Low Back Pain (CLBP) and to explore whether psychosocial variables can explain possible differences.
Methods: 53 Patients (32 men and 21 women) with CLBP were tested twice in a counter balanced design. Pearson Correlation Coefficient of r > 0.75 and non-significant differences on two-tailed t tests were considered as good comparability.
Results: Pearson Correlation Coefficient was 0.75 (p < 0.01). Lifting performance on the WWS was a mean of 6.0 kg higher compared to the PILE (p < 0.01). The difference between the PILE and the WWS was unrelated to psychological variables.
Conclusion: It can be concluded that the PILE and the WWS cannot be used interchangeably. Psychosocial variables cannot explain the differences between both tests.