Level of Evidence for Reliability, Validity, and Responsiveness of Physical Capacity Tasks Designed to Assess Functioning in Patients With Low Back Pain: A Systematic Review Using the COSMIN Standards.
Max Jakobsson, Annelie Gutke, Lidwine B Mokkink and 2 others
PMID 30566577WHAT IT FOUND
The 5-repetition sit-to-stand is the only task with strong reliability and validity, but measurement error was too large to detect minimal important change.
Other common tests like the 50-ft walk also had high reliability but failed measurement error standards.
Key findings
01The 5-repetition sit-to-stand task was the only physical capacity task with positive ratings for more than two measurement properties, including strong test-retest reliability and moderate construct validity.
02Tasks with strong reliability and validity, such as the 50-ft walk and 5-minute walk, displayed strong or moderate evidence for negative measurement error ratings because the smallest detectable change was larger than the minimal important change.
03Most tasks investigated for responsiveness showed limited to moderate evidence for negative ratings, often because they were compared to global disability scales rather than specific capacity constructs.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The COSMIN 4-point checklist was originally designed for patient-reported outcomes, which may not be perfectly suited for assessing physical capacity tasks. Functional capacity evaluations were excluded because the original test manuals could not be obtained due to copyright restrictions. Data extraction was not fully independent; one author extracted the data and a second checked it, rather than two authors working separately. Many studies assessed responsiveness by comparing physical tasks to global disability scales, which measures different constructs and limits the ability to draw firm conclusions about the tasks' sensitivity to change.
Declared interests
The review was supported by AFA Försäkring, Eurospine Research Grants, the Health and Medical Care Executive Board of the Västra Götaland Region, and Vetenskapsrådet. The funders played no role in the study design, analysis, interpretation, or writing of the manuscript.
The easy way to misread this
Do not assume that a change in score on a 50-ft walk or 5-minute walk represents true clinical improvement. These tasks have strong evidence for negative measurement error ratings, meaning the smallest detectable change is larger than the minimal important change, so small score differences are likely measurement noise.