The usability of six physical performance tasks in a rehabilitation population with chronic low back pain.

Objective: To examine the influence of task experience on the difference between test and retest and to assess test-retest reliability and limits of agreement of six performance tasks in chronic low back pain patients. These measures will be used to define the clinical usability.

Design: Test-retest of six performance tasks in a group of patients with no experience and a group of patients after previous experience with these tasks.