Study design: Test reactivity is the based on the idea that experience with a test may affect performance on subsequent tests, independent of what the test purports to measure. The reactivity of a test of lift capacity was studied in a single-blind randomized clinical trial was studied in a single-blind randomized clinical trial in which subjects were assigned to one or two groups. One group received lift testing before and after a therapeutic trial, while the other group received lift testing only at the conclusion of the therapeutic trial.
Objective: To measure the reactivity of a lift capacity test over the course of treatment.
Summary of background data: The reactivity of a test is an important criterion by which an outcome measure must be judged. Change in response to treatment is assumed to be independent of changes resulting from the evaluee's experience with the test, although this is rarely addressed.
Methods: The EPIC Lift Capacity test was administered to 55 patients with low back pain in a treatment program after they were randomized into a pre-test/post-test and a post-test only group. Additional measures were taken on a pre-test/post-test basis for all subjects.
Results: Analyses of variance demonstrated no difference between the randomized groups after treatment. However, the pre-test/post-test group demonstrated significant improvement over the course of treatment. Other measures of outcome were similarly affected.
Conclusion: The reactivity of the EPIC Lift Capacity test was negligible over an 8-week treatment regimen that did not include lifting tasks.